Britbike forum
Posted By: Nick H Lighting no start - 06/03/20 1:40 pm
I so hate to need to make this thread.
I certainly don't know it all but I've been around long enough to know the basics and then some.
Engine has new standard size pistons and rings. Lapped the valves, head appeared in good shape.
Tappets at .008" and .010"
Using this style coil, same one in my running Triumph.
[Linked Image from i.imgur.com]
Spark looks good, big.
Points ignition. Timed with advance locked to 34 BTDC (tricky since I found out too late the flywheel was put on wrong so no timing slot available)
Swapped out Monoblocs (Did try them) for a pair of Concentrics since I'm more familiar with them. Pilot jet clear.
Cold (obviously) compression is 90 both sides. I know that is low but my Triumph is the same and runs fine. Maybe its the gauge-maybe not.
Tried new NGK plugs and new Champion N3.
Starter fluid or gas sprayed in carbs and still not even a pop.

Obviously doing something wrong. Deja vu for the Triumph which I struggled with for longer than I care to say.
Turned out I had a bad Boyer box. Put in points and Vroom!

Any ideas or direction most appreciated.
Posted By: gavin eisler Re: Lighting no start - 06/03/20 2:30 pm
is it sparking on the induction stroke maybe?, check points are opening when both valves are closed for the respective cylinder.
Posted By: Nick H Re: Lighting no start - 06/03/20 2:57 pm
Thanks Gavin, no, it's not that. Just now took off the rocker cover to look things over.

Float level is good by the way. Any higher it would flood.
Posted By: gavin eisler Re: Lighting no start - 06/03/20 6:14 pm
Rags in the inlet tract? Ive done that before.
Posted By: MarcB Re: Lighting no start - 06/03/20 6:58 pm
Electrical short, acting like a kill switch? How's the ZD?

How are you checking spark? Are you moving anything around other than the plug and wire? Are you checking both sides?

Do you see 12v at both coil poles? Good ground on the shared pole?
Posted By: Allan G Re: Lighting no start - 06/03/20 7:46 pm
Are you using the same timing hole on the trigger plate as you are on your triumph? If so this will be the problem, regardless of you having the crank correct when you did it, the spark will be at the wrong point. you want to align the dot with the one that’s anti clock wise aka left hand side of the stator coil.

Otherwise check the Boyer rotor has good magnetism with a screwdriver or spanner (non magnetic) on both of the magnets. I had one which was bad from new. It sparked with the plugs out of the head but not when fitted. Don’t get why. Anyway LP Williams who I bought it off sent me another one straight away - great service!
Posted By: gunner Re: Lighting no start - 06/03/20 8:45 pm
Quote
Timed with advance locked to 34 BTDC (tricky since I found out too late the flywheel was put on wrong so no timing slot available)

I don't get this, how can the flywheel be mounted wrong, is it on back to front? If you cant use the flywheel timing slot how did you time the ignition, degree disc maybe?

From reading your post it sounds like you are using points in which case I believe the AAU has to be bolted into the fully advanced position with the crank also locked into the fully advanced position. Maybe a mismatch somewhere.

Might be worth checking the cam timing as well in case something is amiss.
Posted By: quinten Re: Lighting no start - 06/03/20 9:01 pm
[Linked Image from i.imgur.com]

this coil is wired to 2 sets of points ?
how is it wired ?
Posted By: Nick H Re: Lighting no start - 06/03/20 10:51 pm
Originally Posted by gavin eisler
Rags in the inlet tract? Ive done that before.
Never heard of this. Please explain.
Originally Posted by MarcB
Electrical short, acting like a kill switch? How's the ZD?

How are you checking spark? Are you moving anything around other than the plug and wire? Are you checking both sides?

Do you see 12v at both coil poles? Good ground on the shared pole?
Sorry, forgot to mention I'm using a Podtronics. Wiring is very simple at this point. No headlight/taillight yet.
Checking the spark on both plugs laying on the head.
Points ignition - not Boyer this time.
The center post on the coil is positive from battery and outer negative posts each to a point. (negative ground wiring)
[Linked Image from i.imgur.com]
This is facing front of engine. Timing slot on wrong side!
I measured the piston height with a dial gauge when engine was apart and marked rotor/stator at 34 degrees BTDC
Locked AAU advanced with washer on bolt.

Cam timing set by aligning marks on gears. I don't know much about varying these settings and reasons for it.
Valves seem to be opening and closing roughly when they should.

Thanks for all the replies!
Posted By: chaterlea25 Re: Lighting no start - 06/03/20 11:35 pm
Hi,
Are the condensers in good shape?
If the wires to the points were reversed then the timing would be on the wrong stroke
There was a old post on this type of coil that may help?
http://www.britbike.com/forums/ubbthreads.php/topics/768139/1

John
Posted By: gavin eisler Re: Lighting no start - 06/03/20 11:47 pm
Not so long ago I had an "issue" after a rebuild when the bike would only run on one cylinder, on investigation I found a rag still blocking the inlet port, whoops!
Measuring piston height to guestimate firing angle is not as accurate as using a degree wheel zeroed at TDC using a fixed stop to calibrate. Still it should be close enough to make it run. Are you sure the correct points are firing the correct plugs when the correct cylinder is on comp.?
Posted By: MarcB Re: Lighting no start - 06/04/20 12:17 am
If you've got spark and fuel the way you've described, the only thing left is compression. A compression test won't tell you if you're firing with the valves wide open. An easy test could be to swap the neg wires at the coil.

You should be getting a pop or sputter or something.
Posted By: Danam Re: Lighting no start - 06/04/20 2:18 am
When I first got my A50 I didn't realize the cam pinion rotates in the opposite direction of the crank so I had the points 34' after TDC. wouldn't start.
Posted By: BSA_WM20 Re: Lighting no start - 06/04/20 4:12 am
Well you have something very wrong
So if it were in my shed, the timing disc would come out ( if I could find it ) and get stuck to the rotor nut with a magnet because you are just checking things.
TDC located using a piston stop then a bull dog clip on a fin or a pair of long nose vise grips etc to hang a pointer off.
Then the engine would go through several rotations while I noted the valve opening & closing degrees, and points opening & closing degrees
When the numbers have been measured draw a strait line on some graph paper if you have it.
Make the X axis 7.2" long then every 1/10" = 10 degrees of crankshaft rotation.
Next plot each valve opening and closing plus points opening & closing for each cylinder as individual lines.
When finished you will have 6 partial horizontal lines Left inlet , left exhaust, left points and the same for the right.
Mark TDC & BDC vertically.
If the points or valves are out of time it will now jump up off the page & bite you on the nose.

IF not take a photo & post it here and those who have already made all of the silly mistakes before you will see a repetition of their Boo Boo & set your strait.
Just remember to add 360 deg for things thathappen onthe 2nd rotation.
Posted By: Beach Re: Lighting no start - 06/04/20 1:20 pm
Have you tried smaller gap on spark plugs? I just had a problem with my Atlas. Was doing service on 3 of my bikes and set all plugs to .025" and on the Atlas had a nice spark outside the engine but not even a pop when installed. This bike runs a mag and I checked everything and was almost ready to remove mag when I thought of plug gap. Bit of research found gap should be around.018". Adjusted gap and it fired and ran first kick. Not saying this is your problem, but know for sure it was mine.

Good luck, Bill
Posted By: Nick H Re: Lighting no start - 06/04/20 3:12 pm
Still no go. Thanks for the replies.
I'm definitely firing my sparks on the correct cylinders.
Double, triple checking everything. Put on a degree wheel to confirm valve opening and closing points.
Not with any real accuracy though. Couldn't figure out how to put my dial gauge on.
[Linked Image from i.imgur.com][Linked Image from i.imgur.com]
Sprayed some carb cleaner through the air screw holes and the air entry holes on the back of the carb to see it spray
out the two little holes and confirm my primary idle circuit is clear and working.
Condensers? I'll try a smaller plug gap. Currently at .02"
Posted By: gavin eisler Re: Lighting no start - 06/04/20 3:25 pm
You dont need a dial gauge, you do need to open the valve clearances up to 0.015", as soon as all the clearance is taken up ( judge with a cigarette paper between valve tip and adjuster), that is the opening point, you dont need all 4 reading, so long as the inlet or exhaust is opening within 5 degrees or so of the book number then you are good to go. The reason for the 15 thou clearance is because the cams have slow opening ramps to keep some of the clatter down.
Posted By: Nick H Re: Lighting no start - 06/04/20 3:57 pm
Ah, Thank you! Never heard of that trick!
Posted By: gunner Re: Lighting no start - 06/04/20 4:17 pm
Some random thoughts which may or may not help:-
- is the carb balance pipe fitted?
- are the carbs at least loosly tuned, e.g. throttle cables slack, slides bottoming, pilot mixture 1-1/2 turns out and idle stops turned in slightly?
- any air leaks around the inlet manifolds?
- what do the plugs smell/look like after starting attempts? I would hope that you can at least smell petrol and they arent black/shiny
- is the fuel fresh?
- what about battery charge status, do you have at least 12v and a good earth connection especially to the engine?
- what type of points plate is fitted 4CA or 6CA and what about the AAU springs, is there any slack?
- have you double-checked the cam timing, sometimes there is more than one timing mark on the pinions.
Posted By: wbabojo Re: Lighting no start - 06/04/20 4:21 pm
I had a nightmare like this years ago after a rebuild. I found out that the smooth valve cover was stopping one of the valves from fully closing, due to the aftermarket tappet/replacement valves hitting the inside of the cover. Not immediately apparent, but after starting sans cover, a little work with a grinding wheel and all was well.
Posted By: Nick H Re: Lighting no start - 06/05/20 5:08 pm
Originally Posted by gunner
Some random thoughts which may or may not help:-
- is the carb balance pipe fitted?
Put a blocked off piece of hose on for the balance pipe. Don't exactly remember why but that's what I do.
- are the carbs at least loosly tuned, e.g. throttle cables slack, slides bottoming, pilot mixture 1-1/2 turns out and idle stops turned in slightly?
All yes.
- any air leaks around the inlet manifolds?
Hard to tell when not running. I was using the fat o-rings but they really didn't fit in the groove on the carb, more on top of it.
Today I switched to gaskets.
- what do the plugs smell/look like after starting attempts? I would hope that you can at least smell petrol and they arent black/shiny
They look new. Not wet with gas. Everything smells like gas around the bike.
- is the fuel fresh?
Yesiree
- what about battery charge status, do you have at least 12v and a good earth connection especially to the engine?
13 volts and I believe the earth is good.
- what type of points plate is fitted 4CA or 6CA and what about the AAU springs, is there any slack?
6CA. Should there be slack? I'll look.
- have you double-checked the cam timing, sometimes there is more than one timing mark on the pinions.
I'll be doing this more closely using Gavins method.
Also going to try advancing/retarding the spark at bit.
I tightened up my plug gap on the tight side of .02". Since then I'm at least getting a bit of a "whoom" on kick.
Posted By: gunner Re: Lighting no start - 06/05/20 5:57 pm
Quote
Since then I'm at least getting a bit of a "whoom" on kick.

Sounds like progress, I'm sure the bike will be started soon.
Posted By: gavin eisler Re: Lighting no start - 06/05/20 6:00 pm
If the plugs are not wet, look V closely at the pilot mix delivery holes in the floor of the carb venturi, theres one in front of the slide front lip and one behind it, make sure these are clear. If you spray whatever your go to WD 40 stuff is in through the carb inlet pilot air hole, the one on the bottom lip that isnt plugged you should see stuff coming through the two wee holes ( it will also spray into the float bowl, hold your finger over that hole).
You squished O ring doesnt sound right
Posted By: Nick H Re: Lighting no start - 06/05/20 7:47 pm
Thanks. Checked carb. See post #811453.
Posted By: gavin eisler Re: Lighting no start - 06/05/20 11:49 pm
That 15 thou thing, that not Gavins method, RTFM.
Posted By: Nick H Re: Lighting no start - 06/06/20 12:15 am
Ok, the method Gavin told me about. Sheesh!
Posted By: Nick H Re: Lighting no start - 06/08/20 1:30 pm
Well my cam timing looks good.

What I'm not confident about are my ignition timing marks on my rotor/stator.
If I set the timing advanced to 34 degrees BTDC, when I check it without advance it seems to spark right at TDC.
With an 11 degree AAU, shouldn't it be sparking at 12 degrees BTDC without advance?
This is what I mean about my questionable timing marks.
Recall that I don't have the luxury of a flywheel notch.

Why is it we go to the trouble to set timing advanced anyway?

By the way, I'm at least getting some pops now.

Thanks for the help thus far. I'm a bit dense sometimes.
Posted By: MarcB Re: Lighting no start - 06/08/20 2:29 pm
Originally Posted by Nick H
Why is it we go to the trouble to set timing advanced anyway?

Timing at idle isn't as critical as fully advanced at high RPM. If your timing is off the mark at idle, you might have trouble getting the bike to start. If it's off the mark at full throttle, you might burn a hole in the piston. So it's best to assume setting full advanced timing will get the starting timing in line. If it doesn't, there are certain ways to increase the amount of advance offered by the AAU.

Do you care more about best performance at idle in the driveway, or passing trucks on the highway at 4000 RPM? wink
Posted By: gunner Re: Lighting no start - 06/08/20 3:27 pm
Quote
With an 11 degree AAU, shouldn't it be sparking at 12 degrees BTDC without advance?


I think that's right, an 11 degree AAU will result in 22 degrees of advance, so that should be 12 degrees BTDC, but this is a rough approximation which is why timing is usually set at the fully advanced position.


Another inaccurate way to check is using a rod down the spark plug with a marking for where the fully advanced position is. I don't know what this measurement is on an A65 but you need to find TDC then turn the engine backwards so the piston falls past the marking and then forward until the mark is seen. As mentioned this is not very accurate and I don't know what the measurement is (maybe 0.31" ?) but it may give you a rough idea of whether your timing is in the ballpark or not.
Posted By: quinten Re: Lighting no start - 06/08/20 5:14 pm
Quote
Why is it we go to the trouble to set timing advanced anyway

the full Advance timing is more critical to not putting a hole in the top of a piston
when the bike is running under load .

the idle advance position only needs to start the bike and provide smooth idle .
... with points set at full advance @ 34°
it's assumed that idle advance will be found mechanically when the AAU is unlocked .

you can try it the other way , set the aau timing "slack" at 12° ... this was one of the
old school methods ... before timing lights were common and home shops .

the Springs in your aau maybe to weak to hold 12° ... even at Kickstart RPM ?
Posted By: quinten Re: Lighting no start - 06/08/20 5:14 pm
.
34 degrees is .304 inches BTDC......

or with the old school down hole method .
... 5/16" ... 7.7 mm

slack aau timing at 12° ... down hole is
0.0394 ... 3/64" .... 1mm

once the piston top is located or crankshaft degree is established
any factory mark from rotor to cover pointer should line up .
( if there is no rotor to cover pointer ... make your own )


maybe the aau springs are weak and the aau is advancing , even at kick over rpms ?
or
have you tried switching the plug wire leads ?
Posted By: Nick H Re: Lighting no start - 06/08/20 5:30 pm
Well, that's two suggestions my AAU springs may be weak.
How would I check that? I have another to compare to.
Still curious why it seems to retard all the way to TDC when set advanced at 34. Or nearly - certainly not 12 degrees.
That gives me two different settings depending on whether I set advanced or slack.

Double checked the piston height. Dial bolted to exhaust.

Attached picture tdc.jpg
Posted By: gunner Re: Lighting no start - 06/08/20 6:08 pm
I don't think there is an easy way to check AAU springs and it may be that the springs are from a different bike, hence the problem. I imagine that if you are finding its retarding all the way to TDC then either the springs or AAU/Points are knackered, worth swapping out for a different set but personally I would just fit an EI unit which would solve a lot of problems.
Posted By: Nick H Re: Lighting no start - 06/08/20 6:21 pm
I think you make a good "point".
I do have another set and actually I have a Boyer MKIV on the shelf. The later analog version that is supposed to be better for low battery.
Why am I messing around with these points then?!
Maybe because I fussed around with a Boyer MKIII for a long time on my Triumph before finally finding out it was defective or damaged.
Put points in that bike and started first kick.
I suppose I should give it another chance.
Posted By: quinten Re: Lighting no start - 06/08/20 7:08 pm
Quote
Still curious why it seems to retard all the way to TDC when set advanced at 34. Or nearly - certainly not 12 degrees
Nothing wrong with messing around with points ... if the AAU is taken apart and inspected and lubed .

piston travel isn't linear , it becomes less as it approaches top dead center .
@ 12° it's within 1mm.
@ 10° its 0. 69 mm
@ 8° its 0.44mm

as any aau is used , the Advance stop gets hammered ... and the stop at the end of slot opens .
an 11° aau eventually becomes 12° and gives 24° Of retard from 34 °
if set at full advance ... the idle advance will be less than with a stock new AAU .
( but this doesn't explain why your bike doesn't start )
... if the backing plate Advanced stop shows wear ... its worn .
Posted By: Allan G Re: Lighting no start - 06/08/20 7:50 pm
I maintain your setting the points at the wrong point.

If you’ve fitted the washer under the nut then the idea is that you use it to lock the AAU into the fully advanced position.

If your bike has the facility use the tool to lock your crank in the fully advanced position. If you can’t, then rotate the crank to the strobe timing mark. If you can have someone keep an eye on that mark, I’ve known it to rotate on its own weight and screw your timing up before now.

Screw the points plate so that the screws are centred within the slots. Have the AAU loose on its taper but screw still in place. Have the screw/bolt so that it is applying a bit of pressure or resistance to movement.

Remove the plugs, fit them back into the caps and rest securely on the head. Switch on ignition.

Use a flat blade screw driver and rotate the cam backwards (use the slot on the AAU and rotate it backward until the plugs spark.

Lock the bolt fully. Remove the crank locating tool.

If you haven’t already turn the engine until the high point on the cam (the scribed mark) lines up with the heel of the points. Set the points gap to 0.015”, then rotate the crank 360° and do the same for the other set of points.

Start the bike.

The timing will still be out by some extent. Do not at this point adjust the timing with the main points screws. Use the ones which are for isolated for each set of points.

Time both cylinders.

Set the points gap again. Check the strobe timing again and adjust with the larger screws holding the whole
Plate.

This is how I used to do mine and it was fine every time.
Posted By: Nick H Re: Lighting no start - 06/08/20 8:22 pm
Thanks Allan, I've basically done all those things except that I don't have facility to lock the crank fully advanced
nor do I have strobe timing marks except for those I made myself.

When I convince myself the current points setup is never going to work, I'll take this AAU out and compare to my other one
and maybe just install the Boyer at that "point".
Posted By: gavin eisler Re: Lighting no start - 06/08/20 9:06 pm
One of the many mistakes I have made, when first timing my A65, assumed the points cam rotates the same way as the crank, it doesnt. Just a thought.
Posted By: Allan G Re: Lighting no start - 06/08/20 9:28 pm
Originally Posted by Nick H
Thanks Allan, I've basically done all those things except that I don't have facility to lock the crank fully advanced
nor do I have strobe timing marks except for those I made myself.

When I convince myself the current points setup is never going to work, I'll take this AAU out and compare to my other one
and maybe just install the Boyer at that "point".

I did remember part way through writing about your fly wheel being the wrong way around. One of my cranks was the same so I feel your pain. If you can make a piston stop tool this would help a lot.

As you don’t have any marks on your rotor apart from your own, have you tried turning the rotor around? There should be some marks on the other side of it.

If your timing the AAU at full advance it could be totally clapped out and still function, wobble with the cam on the shaft will cause erratic timing and weak springs will just cause it to advance early. The first you’ll feel when you have the unit in your hands, the second you’ll see when you rev it up on the strobe light. Eurotrash Jambalaya in the states sell really good springs (they sell good springs in general but obviously were on about advance springs) they go full advance at 3000, with a tweak I tightened mine up to 3500, the bike ran well like that.

Find the spark timing in the same method as I mentioned?...


Originally Posted by Allan G
Screw the points plate so that the screws are centred within the slots. Have the AAU loose on its taper but screw still in place. Have the screw/bolt so that it is applying a bit of pressure or resistance to movement.

Remove the plugs, fit them back into the caps and rest securely on the head. Switch on ignition.

Use a flat blade screw driver and rotate the cam backwards (use the slot on the AAU and rotate it backward until the plugs spark.

Lock the bolt fully. Remove the crank locating tool.


If you haven’t, give it a try, it’s imperative that you turn the cam so it’s opening up the bob weights, not the other way around I tried with the light bulb method as shown in the workshop manual, not only did I find it more of a faff but for some reason it didn’t want to work for me. This method works every time from Bantam to A65, it even works on bikes which use Hall effect sensors on the timing and the window on the rotor is quite large.


One other thing to check is that you have a BSA Type AAU and not a triumph type or unit single type. With the triumph/unit single AAU unit as soon as it starts to open up it will retard the ignition. The 11° AAU strikes me as puzzling, AFAIK A65’s (certainly all the later ones with 6CA cams) were 12° not 11°.
Posted By: NickL Re: Lighting no start - 06/09/20 5:02 am
Originally Posted by Nick H
Well, that's two suggestions my AAU springs may be weak.
How would I check that? I have another to compare to.
Still curious why it seems to retard all the way to TDC when set advanced at 34. Or nearly - certainly not 12 degrees.
That gives me two different settings depending on whether I set advanced or slack.

Double checked the piston height. Dial bolted to exhaust.


The 1/2 timing pinion rotates at 1/2 engine speed so 12 degs on the points cam = 24 degs at the crank.
Allowing for backlash in gears and wear in the mechanical assembly you may see a few degrees difference at
the crank/piston height.
Spend a couple of hundred bucks on an electronic ignition and life will be simpler.
My2c
Posted By: MarcB Re: Lighting no start - 06/09/20 11:46 am
Originally Posted by NickL
[quote=Nick H]
Spend a couple of hundred bucks on an electronic ignition and life will be simpler.
Hmm, not necessarily. If the timing marks are non-existent then it's possible that nothing is lining up. Nothing will line up with EI either. Don't get me wrong, I'm a big proponent of EI but replacing points with EI shouldn't be "to make it work" but rather "to improve on the working process".

If replacing the points with EI helps in this case, then the original parts were wrong (either points or AAU) and a different set would have helped as well.
Posted By: Nick H Re: Lighting no start - 06/09/20 12:31 pm
Originally Posted by MarcB
Originally Posted by NickL
[quote=Nick H]
Spend a couple of hundred bucks on an electronic ignition and life will be simpler.
Hmm, not necessarily. If the timing marks are non-existent then it's possible that nothing is lining up. Nothing will line up with EI either. Don't get me wrong, I'm a big proponent of EI but replacing points with EI shouldn't be "to make it work" but rather "to improve on the working process".

If replacing the points with EI helps in this case, then the original parts were wrong (either points or AAU) and a different set would have helped as well.
Thank you. Exactly why I am reluctant to go to the effort to install the Boyer I have on the shelf here.
Also have some Lucas springs #54417992 which I think are supposed to be stronger springs
I feel points are somewhat easier to diagnose and troubleshoot.
If there is a problem with my timing marks, which I don't think so as I've checked them all different ways, then the EI won't work either.
Maybe it's a carb or other problem.

Alan: Here's my other BSA AAU, 11 degree. Maybe early 4CA part.
Curious. Doesn't have the hash mark to set points on the front.

.[Linked Image from i.imgur.com][Linked Image from i.imgur.com]

Gas tank slipped off the shelf and got a dent. Not a perfect tank to begin with but I think I have to step away from this
bike for a couple days before I start throwing tools!
Posted By: Allan G Re: Lighting no start - 06/09/20 6:26 pm
From researching some old posts it does look like yours is a 4CA AAU. these are best turning into spinning tops for kids to play with, their cam design caused a lot of engines to go bang (the dwell is something like 170 degrees, the downside was this caused some points bounce and sparking to occur. The 6CA is something like 86°) for a few years until BSA realised the issue and come mid 67 created the -Y bikes which apart from the oil system upgrade also had the cam upgrade to 6CA. The points plate was also updated from the type which had the condensers mounted at the points, to a provision under the seat. This allowed the points to be adjusted/timed individually rather than setting it somewhere in the middle or adjusting the points gap on individual points in attempt to try and time the cylinders accurately.


Older Britbike post if you scroll down to RF Whatleys comments and have a read. RF is still a member of this board and very knowledgable on what rolled out of the doors of Lucas.
Posted By: Nick H Re: Lighting no start - 06/09/20 7:29 pm
Well that settles that! I'll be installing the Boyer. Hope it helps the starting too.
Thanks Allan for that esoteric bit of info! You may just have saved my engine.
Posted By: Richrd Re: Lighting no start - 06/09/20 7:50 pm
You are using NEW plugs, right?

The pod has nothing to do with this

Figure out how to run a jumper wire from battery to coil and eliminate all else

If you are using points as I think, are they CLEAN?

Any flim on the contact surface will screw things up.

Why are you messing with cam timing? Is this a new build or have you had the cam out?
Posted By: Allan G Re: Lighting no start - 06/09/20 8:17 pm
Originally Posted by Nick H
Well that settles that! I'll be installing the Boyer. Hope it helps the starting too.
Thanks Allan for that esoteric bit of info! You may just have saved my engine.

The Boyer is less faff to set up and fit and forget (I’m a Pazon advocate myself but each to their own)

I was hoping to find that I could find an image showing the cam looking like a triumph type but sadly in one way not so. So I stumbled across the old thread, it did teach me something also so that’s good news there, I thought they were ALL 12° but it seems not only the 6CA type.

Fingers crossed with the Boyer install. If this doesn’t work it might then push us all to look down a different avenue.

Another one to try if your sure you have it set right but it won’t go, open the throttle fully and crank it over like that, I usually do it with a flooded engine but a troublesome one it tends to work with too (providing everything else is correct)
Posted By: NickL Re: Lighting no start - 06/09/20 11:27 pm
Originally Posted by MarcB
Originally Posted by NickL
[quote=Nick H]
Spend a couple of hundred bucks on an electronic ignition and life will be simpler.
Hmm, not necessarily. If the timing marks are non-existent then it's possible that nothing is lining up. Nothing will line up with EI either. Don't get me wrong, I'm a big proponent of EI but replacing points with EI shouldn't be "to make it work" but rather "to improve on the working process".

If replacing the points with EI helps in this case, then the original parts were wrong (either points or AAU) and a different set would have helped as well.


You can get it running with an EI by putting a screwdriver down the plug hole and marking it at somewhere around 8mm.
It's a bloody site easier than messing with the points cam, replacing springs, checking wear on advance assembly etc..
When i see a points plate/mech advance that isn't worn or clapped out on one of these old crates i'll advise to use it.
Posted By: Nick H Re: Lighting no start - 06/10/20 1:53 pm
Ooops, Wait! Looks like I had a 12 degree AAU in after all. Really must take notes in the future.
New plan is to put my strong springs on the AAU and give it another go. One strong spring, two?

Richrd: New points, new plugs. Yes, motor was apart.
Posted By: Allan G Re: Lighting no start - 06/10/20 2:07 pm
Always fit a matched pair of springs, so two.
Posted By: kommando Re: Lighting no start - 06/10/20 4:54 pm
Do yourself a favour, once you get it started either go 6CA or electronic and dump the 4CA AAU.
Posted By: Andy Higham Re: Lighting no start - 06/10/20 6:49 pm
How worn are your idler bushes?
The idler bushes are quite small and even the slightest amount of wear will throw the timing out by a random amount
Posted By: quinten Re: Lighting no start - 06/10/20 8:29 pm
The Springs don't have to be the same size ,
You actually get a more complex Advance curve by using different
size springs .
1. A weaker or primary spring , able to hold the advance at idle rpms
and then
2. a slacker secondary spring that only comes on ... after the the primary spring is partially stretched.

... but here , we dont know whats really going on , or if this is even an ignition problem .
so stronger Springs will help hold idle rpms .

which Direction is the points cam advancing ?

Someone earlier brought up the point that you might have a Triumph AAU .
i dont remember if the correct Direction was ever verified.
BSA runs points run on a counter shaft , so the aau spins opposite the engine Direction .
... the points cam advances into its own Direction ... counterclockwise .
.
Posted By: gavin eisler Re: Lighting no start - 06/10/20 10:46 pm
Looking at the pic it appears to advance the right way.
If its a 4 CA make the toy that Allan suggests, then fit EI.
Posted By: Nick H Re: Lighting no start - 06/10/20 11:43 pm
I know it's confusing but I never had 4C point or AAU in.
[Linked Image from i.imgur.com]
And yes, it is a BSA CCW advancing AAU.

Andy Hingham: Idler bushes? That the idler gear runs on that the points are attached to?
All I can say is that all those bushes in the case looked real good. Lowish mileage engine I believe.
Posted By: gavin eisler Re: Lighting no start - 06/11/20 12:03 am
Could be the lighting, I only see one points wire. Looks quite unmolested.
Posted By: Nick H Re: Lighting no start - 06/15/20 7:03 pm
I believe I've discovered the issue.
Multiple checks of everything did another compression test with a bit of oil.
No change and a bit below 90 both cylinders.
Leakdown test with my cobbled tool.
[Linked Image from i.imgur.com][Linked Image from i.imgur.com]
Hissing all around head gasket far as I can tell. Went from 100psi to 65psi in one minute.
I used an annealed copper gasket with some spray copper seal but after torquing the head once I took it off
briefly (forget the reason) and remember thinking I should re-anneal - but didn't!
Also torqued the outside bolts by feel. Really should get a tool to put a torque wrench on those.
Slight leak out the left exhaust pipe also.
Let's hope this is my no-start issue!

Comments welcome.
Posted By: Nick H Re: Lighting no start - 06/16/20 8:05 pm
Ok, so I annealed the had gasket carefully and sprayed with copper seal stuff.
Also lapped the exhaust valves.
Now my compression is no better. Leak down test revealed air leaking out all the valves to some degree.
Hard to tell if its leaking at the head gasket.
This is interesting as I tested the head by inverting and filling with kerosene. Held the level for quite a while
but did eventually go down.

So what do I need to do? Remember I'm still fairly new at this.
Have the valve seats done at - a motorcycle shop? Buy new valves too? Springs?
Why didn't my lapping of the exhaust valves work?
Posted By: BSA_WM20 Re: Lighting no start - 06/17/20 8:37 am
Take the head & valve to a motorycle repair shop or a lawnmower repair shop
The kit used for A65's is the same as used for Briggs & Stratton ( plus 1/2 the other stationary engines ) .
Pick a shop that has lots of old machines for sale that they have repaired for resale.
If you have pulled the valves out of the head should be a 20 minute job at whatever they charge per hour.

You can do it yourself withthe Neway gear which is hard to make a mistake with and good enough for a normal street rider.
However the kit is not inexpensive so unless you are intending to this type of work regularly not an economic outlay .

valve lapping is not as easy as many would suggest and if the guides are not as good as they could be then getting an acceptable job is quite difficult.
Posted By: Dave Martin Re: Lighting no start - 06/17/20 12:01 pm
So obviously the valves are A problem, the question is are they THE problem?
I would have expected that at 90psi there was enough compression to get you something, might run as rough as a bears arse, but i would have thought it would at least make an effort.

Have been watching this thread for a while and cannot get the timing out of my head. Are you absolutely sure that you have timed it at 34 BTDC and not 34 ATDC? i.e. you got the direction of rotation right?
Please don't ask me why this thought will not go away, I was a lot younger then.
Posted By: Beach Re: Lighting no start - 06/17/20 12:24 pm
Originally Posted by Nick H
Ok, so I annealed the had gasket carefully and sprayed with copper seal stuff.
Also lapped the exhaust valves.
Now my compression is no better. Leak down test revealed air leaking out all the valves to some degree.
Hard to tell if its leaking at the head gasket.
This is interesting as I tested the head by inverting and filling with kerosene. Held the level for quite a while
but did eventually go down.

So what do I need to do? Remember I'm still fairly new at this.
Have the valve seats done at - a motorcycle shop? Buy new valves too? Springs?
Why didn't my lapping of the exhaust valves work?

Hissing around head? Mix a dish soap- water solution and wipe around to see if bubbling occurs. You will never find this problem if you don't follow exact procedures for each check. If you have precisely followed all steps, I would go back to the start. Do one thing at a time. i have read stories about proper annealing of gaskets and don't think many do it properly anyway. I do not even try, but I definitely use a torque wrench and tighten in proper sequence in steps. I also feel that the valves are good enough to run or at least give signs of life if all else is right. A lot of thing you have checked would keep from running at peak, but imo would not keep it from starting.

These old bikes can be frustrating at times. I feel your pain.
Posted By: Beach Re: Lighting no start - 06/17/20 1:16 pm
I didn't see here where you took Allen's suggestion to use a piston stop to find tdc for degree wheel. It's the only way to be accurate with timing and should not be overlooked considering the mountain of problems you're having. Also either didnt see or missed how you did your timing side gear alignment.
Posted By: Nick H Re: Lighting no start - 06/17/20 4:09 pm
Thanks for the replies.
I have double checked most things so many times it's ridiculous.
I am well aware of the anomaly of the BSA points rotating clockwise and the rotor traveling CC. Definitely BTDC.
Funny, I have a friend of many years named David Martin who is a mechanic (ten car garage at home full on 60's muscle cars- all mint all running)
who thinks it should start as is too. He has 2 Harley baggers but has seen a lot.

I spent a long time getting float heights correct. More on this later maybe but don't want to turn this into a float height thread.

I don't know what else it could be but the valves and compression. Was actually a bit under 90 psi and as I said, on leakdown was hissing obviously
out the carbs and exhaust. Dropped from 100 PSI to 65 PSI in a minute.

Beach, when apart I used dial gauge to find my timing point, if you remember I have no usable notch in the flywheel so this is what I had to do.
A few posts back I included a photo of my dial gauge through the plug hole as I was double checking that.

Valve timing was simply lining up marks on the gears. Fine points of adjusting valve timing beyond me but I did check the valves opening and
closing points with degree wheel on rotor side.

Machine shops are rare around here and can be pricey. One gave me an estimate of $400 to do the valves and mentioned he thought maybe
would need new guides. (I don't think so) Only an estimate but in my experience you don't often get a lower price when a vendor puts out
a number. Kind of expensive, yes?

Oh, also, I have a decent torque wrench and now have the 15mm crow foot to do the nuts.
Posted By: Beach Re: Lighting no start - 06/17/20 4:33 pm
That's a lot for a valve job, imo. Maybe your friend could suggest someone.
Posted By: Andy Higham Re: Lighting no start - 06/17/20 5:37 pm
Has anyone asked the obvious question?
Are the leads on the correct plugs? if the AAU or points plate have been off the bike it could be timed on the wrong cylinder. Try swapping plug leads
Posted By: koan58 Re: Lighting no start - 06/17/20 5:38 pm
"I don't know what else it could be but the valves and compression. Was actually a bit under 90 psi and as I said, on leakdown was hissing obviously
out the carbs and exhaust. Dropped from 100 PSI to 65 PSI in a minute."

This sounds like you've already identified a major problem, whether it is the only problem who knows. Assuming the head gasket is sealing, and the leakage is not coming from there and being confused with valve leakage, then:
-Whether or not the guides are knackered, some or all the valves are not sealing during the leakdown test.
This could be due to tight valve clearances, bent valves or poor valve/seat contact surfaces.
Do you find the hissing in all the ports, or just some?

Try opening the clearances (silly big) and repeating the leakdown test. If the hissing still comes from the in/ex ports (note which ones) then the valves must come out, no question.

Even with worn guides/stems it is easy to get good sealing of valve/seat surfaces in a static test like leakdown, so you will have to check the guides/stems as a separate matter.
If you find the guides need replacement, that maybe something for an engineer, depending on your confidence/ability.

But getting the valves out, checking them and basic reconditioning is well within most folks scope. No need to spend $400 at this stage, IMHO.
Enough for now.
Posted By: Andy Higham Re: Lighting no start - 06/17/20 6:15 pm
If the guides are worn it is better to get guide liners fitted. Less chance of developing a loose guide
Posted By: Nick H Re: Lighting no start - 06/17/20 8:31 pm
It sure isn't tappet lash clearance. Leakdown is done at TDC compression. Valves fully shut.

Plugs are sparking on correct cylinder. Ask me again and I'll tell you the same. smile

Here's something. Valves spring free lengths are way off.
I believe should be

Outer: 2 1/32"
Inner: 1 5/8"

Mine are

Outer: 1 3/4"
Inner: 1 1/2"
Posted By: MarcB Re: Lighting no start - 06/17/20 9:03 pm
Originally Posted by Nick H
It sure isn't tappet lash clearance. Leakdown is done at TDC compression. Valves fully shut.
Right, or are they??? That is what was being asked... are you certain they are fully closing?

Originally Posted by Nick H
Here's something. Valves spring free lengths are way off.
I believe should be
Take a look at my thread here and see if that's what you've got: http://www.britbike.com/forums/ubbthreads.php/topics/776512/a65-progressive-valve-springs
Posted By: Nick H Re: Lighting no start - 06/17/20 10:05 pm
Yes I am certain!!! Valve cover was off.

These outers do look progressive, don't they?
Does that make them OK?
[Linked Image from i.imgur.com]
Ordering new anyway.
Posted By: koan58 Re: Lighting no start - 06/17/20 10:55 pm
Whether or not the springs are ok makes no difference to your leakdown observation.
Posted By: Nick H Re: Lighting no start - 06/18/20 12:58 am
Alright. I thought possibly weak spring could prevent valves from closing tight.
So why should or shouldn't I care about the springs?
Posted By: koan58 Re: Lighting no start - 06/18/20 1:15 am
You should care about the springs as well as every other part of the motor, but the immediate issue seems to be with valve/seat sealing.

The springs may or may not be ideal, but are unlikely to have much relevance to your leakdown observations.
Posted By: Beach Re: Lighting no start - 06/18/20 1:22 am
They are good enough to check the seating of valves. The valves should have gone back in same position.
Posted By: koan58 Re: Lighting no start - 06/18/20 1:59 am
Well hopefully they will, but while they're out, now is the time for a little wiggling to see how floppy the valves are in the guides ( any more than about 10 thou head shake is worn) but more relevantly now is the time to examine the valve and seat surfaces.

If in any doubt it is time to try a little lapping with fine paste.

Then look at the surface of the valve, if it shows just one patch of grinding, the valve is bent.

If the valve is straight, continue with careful lapping to get a good contact surface, using the finest compound. Don't be tempted to use coarse to speed it up.
You should end up with something like a continuous smooth contact surface between valve/seat at least about 1/16+" wide.
Posted By: Dave Martin Re: Lighting no start - 06/19/20 12:14 pm
By the sound of it the motor is now in pieces, but when you were trying to start it were you just kicking it or did you try a bump start, preferably down hill where you can get a bit of speed up? I my experience starting like that can get over a load of starting tuning issues (timing, mixture etc.) then at least you will know that the bugger runs, and all you have to do is find out why it wont start!
Posted By: gavin eisler Re: Lighting no start - 06/19/20 1:19 pm
last valve springs I bought from SRm were not the book length, they were Inner 39.87 mm Outer 41.75.
these are a common Triumph type, they work fine for A65s.
Book figs for BSA springs, inner 36.5 mm , outer 44.5..

I dont think this is why your bike wont run.
Even at 90 psi it should show a glimmer of life. Side valves will run on less.By all means fix all the head leaks.
Lapping valves , are you using continuous rotation, or oscillate lift repeat?
Posted By: Allan G Re: Lighting no start - 06/19/20 2:16 pm
I still think this is timing related,

If you can fit a washer so that it goes over the AAU inner but pressed against the cam to fix the cam in the fully advance position, take the plugs out, put it in 4th.

Remove the primary cover if you do not have the provision for a timing cover on the primary cover and find the 34 degree mark.

with the plugs out you can turn the engine over and see the spark, with the plugs rested on the head connected to the ht leads the plugs will spark regardless of how slowly the crank is being turned. this will be the most accurate way of checking that the timing is correct without being possible to run the engine....

You can do this even with the head off. Infact if you don't have any strobe timing marks, with the head off if you have a DTI and magnetic stand, you can pretty accurately get the measurement down the bore.

You can do this more accurately if you have a timing disc also. This is most important if you are establishing exactly where the 34 degree mark should be. You can be a few degrees either way with the other method but this would be accurate enough for the bike to start and run.
Posted By: Nick H Re: Lighting no start - 06/19/20 6:51 pm
Thanks for the replies.'

I think my timing is good, Allan. I use the washer on the AAU to lock it and I set the points by watching 2 Ohm meters.
I found my 34 degree mark using the dial gauge and checked it with degree wheel.

I dropped the head at the pricey machine shop. Not needing new guides I would hope i will get a quote much under $400.
They are busy this time of year of course, so hoping to hear something next week.

When I lapped the valves, I used random motions in both directions.

I could push start it down our hill but I'd be stuck if it didn't start!
Posted By: Andy Higham Re: Lighting no start - 06/19/20 6:59 pm
Any sign of marking on the valves and seats should be removed by re facing the valves and seats, the last ones I had done cost me £25 for a single cylinder side valve engine. If you try to lap marks out it puts ridges in the seat and will never seal
Posted By: Nick H Re: Lighting no start - 06/19/20 7:22 pm
Thanks.
Whatever the no-start reason I need to address the low compression.
A while ago I made this leak down tester following directions I saw on line.
[Linked Image from i.imgur.com]
It's basically two pressures gauges, one with a valve, and a pin hole between them.
In use, the small gauge measures the pressure going in and I thought the large gauge was supposed to measure
what pressure remained, the difference being the loss.
I get no reading at all on the large gauge so I don't know what that means. 100% loss?
[Linked Image from i.imgur.com]
What I do see is fairly rapid drop in pressure over time.
Posted By: Gordo in Comox Re: Lighting no start - 06/19/20 8:18 pm
Nick: How long do you expect a good engine to hold the compression? Even assuming perfect valves the rings will not hold the pressure for an extended length of time. The air slowly seeps out past the rings and through the ring gaps. For example my A65 is a good runner, normally starts on first kick but I can, with just my hand, slowly turn the engine over through the compression strokes. After all these are only 325cc cylinders so a little seepage will dramatically reduce the pressure reading.

Gordo
Posted By: gunner Re: Lighting no start - 06/19/20 8:45 pm
I don't know how you're doing the leak down test but the basic idea is as follows:-
- set the cylinder being tested to TDC using a rod/dial gauge down the plughole, both valves should be closed (obviously).
- lock the engine in place, this is important as any pressure introduced to the cylinder will turn the engine and may result in the opening of the valves, thereby causing pressure loss.
- connect the leak down tester to the spark plug hole of the cylinder being tested. Add pressure to the cylinder until it's about 100psi, then stop adding pressure. Immediately note how much pressure is in the cylinder being tested using the larger gauge, the pressure will leak out of the cylinder so it's essential to take any measurement in the first few seconds.
- ideally, this test should be done when the engine is warm when the rings will be much better at sealing, cold engines and those never run will not seal their rings too well.

Quote
I get no reading at all on the large gauge so I don't know what that means. 100% loss?

The engine must be at tdc and locked otherwise it's likely the piston will move and valves open.

Quote
What I do see is fairly rapid drop in pressure over time.

The timing should be done over the first few seconds, the pressure will drop over time.
Posted By: Ignoramus Re: Lighting no start - 06/20/20 2:06 am
lots of good comments about mechanical side of things but none of these should stop it actually starting or at least attempting to start (other than the obvious timing) . that said friend of mine with a Goldie drove himself round the bend chasing his tail till he found melted alloy under one of the valves (he has cooked a piston and blew a hole in the top) ......but that was a single........like i said to him 'well the melted alloy has to have gone somewhere"

so lets take a look at some of the obscure stuff

pretty high up my check list would be stale fuel ( you said, i think bike had been off road for a bit) ....sorry if you have already filled it with new fuel, ......try disconcerting the tank and filling just the carb bowls with some new fuel ......if it still doent at least fire up i would be starting to look for electrical faults

like they say 80% of carburation problems are electrical
Posted By: Nick H Re: Lighting no start - 06/20/20 11:43 pm
With the head at the machine shop, I decided to try to fit my spare head and see how the compression is.
I don't want to use this head because it has been severely skimmed, has exhaust stubs welded on, etc but it's valves look
pretty good and hold kerosene overnight.
[Linked Image from i.imgur.com]
But I've come to see that holding liquid and holding air are quite different things.

Well, no surprise really, the compression has not improved.
I don't suppose it matters that I did not install carbs, pipes or valve cover.
I can hear air hissing in the crankcase so I'm losing compression past my rings.

When I got this bike I was surprised that the cylinder measured no discernable wear.
Using my Starrett gauges at times it actually seemed to measure less than 75 mm, impossible of course.
So naturally I honed it and bought standard pistons and rings. JCC pistons and Hastings rings.

When installed though the ring gaps measured wide, about .016"-.018"
Decided to let this go after reading several posts with varying opinions.

I'm not confident about my measurements of bottom of skirt clearance but my notes say .003"-.007"
The piston is .012" wider perpendicular to the pin than with it so I didn't know where to measure.
Top of skirt I had measured .007"
I'm not that good with a feeler gauge anyway. And not a lot of experience with micrometers.
But I do trust my initial bore measurement as I checked it many times and my calibration.

So what is this all telling me?
Where is my compression?!
Posted By: Nick H Re: Lighting no start - 06/25/20 8:36 pm
Local machine shop looked at head and quoted $400 for new guides and cut seats.
I provide parts. New valves, guides, springs I estimate $300.
Took a pass.

But did order new valves and springs.

My valve stems measure a few thous too small. I imagine the new valves will tighten up the guide situation.
Are newly cut seats required with new valves? Is lapping required?
Posted By: gunner Re: Lighting no start - 06/25/20 9:07 pm
Sounds like you local machine shop is taking the p*ss, there is no way it should cost that much, shop around for some better deals.

The process of installing new guides goes something like this:-
- old guides are punched out of the head
- guide bore in the head is checked for size in-case oversize guides are needed
- head is heated in an oven, new guides are cooled in the freezer and the guides are then installed, hopefully using a guide tool to align them with the valve seat
- valve guides are then honed to match the valve stem diameter
- the valve seats are then cut ideally using 3 angle cut
- some modern machine shops using Serdi and other valve guide honing and seat cutting tooling claim that their accuracy is so good that no lapping is necessary, assuming the valves are in good condition

This type of renovation is standard business for many car engine re-conditioners so with only 2 valves instead of 16 or 32 I don't see how they can charge that much. Maybe you could try a motorcycle specialist such as E&V engineering who have huge experience with BSA's etc. see https://www.shopevengineering.com/
Posted By: Allan G Re: Lighting no start - 06/26/20 6:13 am
As Gunner said, I’d sell the head on if I had to pay that much and take my chances with another.

Regarding valve stem. Different makes are different. I’ve had some which have been under size compared to original (probably my 8mm instead of 5/16)and some which are a a faction over. I’ve found the SRM ones are a fraction over and each set I fit need the guides reaming to size. This isn’t a problem, the valves cost about £2 more than no name ones and the guides have never had to be replaced. A decent machine shop will cut the seats for next to nothing, or spend some time and lap them in by hand, hopefully the valve seat recession isn’t too deep.
Posted By: Dave Martin Re: Lighting no start - 06/27/20 2:04 am
i hope you get the darn thing started soon, it is beginning to bug me (so lord knows what it is doing to you!).
back to basics ... suck , squeeze, bang, blow.
At 90 psi there should be plenty of squeeze,
you seem happy with the bang bit (though I still doubt the timing!)
So that just leaves the suck and blow bits. Now I don't know much about twins, as I have said before, never saw the point of more than one cylinder, but on the unit singles it seriously matters which way round the cam followers are.
Got one the wrong way round on my B44 once and it simply would not start. Timing was good, compression reasonable, valves opened and closed at about the right time, but it would NOT run. I presumed that the valves were staying open at inappropriate times.
Posted By: Nick H Re: Lighting no start - 06/27/20 3:03 pm
Meanwhile, this abomination that I bought for the '70 engine and other parts I threw a weak battery on, gassed it up and it started up easy. Has clapped out old carbs, balance pipe was off, single coil, wired by a madman.
[Linked Image from i.imgur.com][Linked Image from i.imgur.com]
Gotta love the hardtail with the springs on the Harley fender. Soft ride for the car battery on the sissy bar.
Posted By: kevin Re: Lighting no start - 06/27/20 9:56 pm
i would ride that around just to annoy people
Posted By: Nick H Re: Lighting no start - 06/28/20 12:32 am
Ha! I should. It's loud as hell!
Posted By: Nick H Re: Lighting no start - 07/02/20 10:12 pm
WhaLah! She started!

Put in new valves and springs. Cold compression was still low. Put some oil down the plug holes which if you've ever done it, makes the bike hard to kick. Had to do the jump kick and Vroom! Lots of smoke of course. Ran it for a couple minutes and when I turned the key off, she kept running. Had to pull off the plug wires. I guess it was dieseling.

I think compression is the issue. I'll see how things go with the ignition strobed and the carb dialed in and a bit of break in.

Whew!!!!
Posted By: gunner Re: Lighting no start - 07/02/20 10:38 pm
Well done smile
Posted By: htown Re: Lighting no start - 07/03/20 3:09 am
True dieseling is when the engine keeps running with out the spark plugs firing. Pulling the plug wires shouldn't make a difference, though it might just be a coincidence that it quit at the same time. Generally if dieseling it's running very rough because ignition is at the wrong time. Timing, carbs, wrong or bad plugs, air leak, a hot spot in the combustion chamber are possible causes of dieseling. Maybe remote chance but is your ignition or kill switch working correctly. If you are using ei you could make sure it turns off the lead to the box.
Posted By: Allan G Re: Lighting no start - 07/03/20 6:43 am
Originally Posted by htown
True dieseling is when the engine keeps running with out the spark plugs firing. Pulling the plug wires shouldn't make a difference, though it might just be a coincidence that it quit at the same time. Generally if dieseling it's running very rough because ignition is at the wrong time. Timing, carbs, wrong or bad plugs, air leak, a hot spot in the combustion chamber are possible causes of dieseling. Maybe remote chance but is your ignition or kill switch working correctly. If you are using ei you could make sure it turns off the lead to the box.


Another one to add to that last comment is, where in the chain does the regulator connect into the loom, which side of the switch. It wants to be the same side of the switch as the battery... otherwise the bike will keep running.
Posted By: Nick H Re: Lighting no start - 07/03/20 2:06 pm
Originally Posted by Allan G
Another one to add to that last comment is, where in the chain does the regulator connect into the loom, which side of the switch. It wants to be the same side of the switch as the battery... otherwise the bike will keep running.

So the key switch should shut off the regulator? That's the problem! Didn't really make sense that it would diesel. Allan G, you're batting 1000%.
Posted By: Allan G Re: Lighting no start - 07/03/20 7:22 pm
Yes, if I read you correctly.

A better explanation would be (ignore the red wires for now) battery to ammeter if fitted,

Ammeter on the other side is the Reg rec.

Then from the same side of the ammeter (should be a white with brown stripe if pre oif, oif doesn’t have ammeter and Reg Rec can go direct to battery) to the ignition switch.

Other side of the ignition switch then feeds: ignition, auxiliary. And lighting (although if you want lighting to be powered when the key isn’t in then you can connect this to the ammeter on the same side as Reg rec)

From memory anyway, but I don’t think it’s wrong or far out.
Posted By: Ignoramus Re: Lighting no start - 07/03/20 8:13 pm
sure sounds like an intermittent electrical problem to me (those can be a real [***]) ............hot wire it to by pass the switch and see how you go then ...........i did suggest electrical problem like 20 posts ago but that didn't seem to attract any comments
Posted By: quinten Re: Lighting no start - 07/03/20 9:08 pm
Allen got it right .
here's a picture that may help .
Your head light switch may be different , but ...
[Linked Image from i206.photobucket.com]

stick join the black regulator output wire
to the brown /w white harness wire ... anywhere between ... the ignition switch and the fuse at battery ... so regulator is fused .
if there is an ammeter ... it needs to be wired as shown ... to show amps in or out of the battery .
( fuse size on image is wrong )... should be 20 amp.

... from the diagram you can see both the regulator output and the battery are on the same side of the ignition switch .
so switched at the same time .

with no ammeter
you could also join the black regulator output ... right to the battery negitive
... but now the regulator needs its own fuse .
if you don't want to add a second fuse
wire at the ammeter or where the ammeter is shown on wiring diagram
Posted By: Nick H Re: Lighting no start - 07/04/20 12:44 pm
Thanks. Yes I did add a fuse for the regulator.
The wiring is simple and ad hoc done by me with little consideration for wire color.
Now making it street legal adds a lot of complications like brake light switches for front and back brake and turn signals (not legally required but I like to have them in todays traffic).
Posted By: Nick H Re: Lighting no start - 07/04/20 5:36 pm
Rode the Lightning around the yard today. Clutch is easy and shifts without any effort or noise.
Had to oil the pistons for compression to start it though. Gasket seal is good but apparently I have leaks past the pistons and rings.
Or the valves still or both. New valves fit the guides better and the head held kerosene overnight, something the old valves didn't do.
Leakdown test was only slightly improved though. I could hear leaking past valves and inside case both.

The bores are 2.95" everywhere with little variation so my standard pistons and rings should be correct.
Ring gaps were .016"-.018". Would it help if I installed +.020" rings and gapped tighter?

Pleased to know my carbs, timing, wiring etc are good though. Big thrill to finally hear it fire up.
Posted By: quinten Re: Lighting no start - 07/04/20 7:33 pm
Quote
Would it help if I installed +.020" rings and gapped tighter

Not in my opinion .
Larger rings will impart more friction throught all 4 strokes ... not just the power stroke .
ring drag is necessary to seal but it's also a waste of power .
spring load is supposed to be just enough
and
compression and power stroke get behind the rings and add to the rings spring-seal .

Someone else , the engine designers and ring- manufacturers have already done the hard thinking on this .
each oversized is designed to work in a bore-range .
Posted By: Nick H Re: Lighting no start - 07/04/20 7:58 pm
Ok, then I'm thinking i must need a rebore to +.020" and maybe the valve work as well to get compression where it should be.

This project has fought me all the way but I still love the bike and the A65.

[Linked Image from i.imgur.com]
Posted By: quinten Re: Lighting no start - 07/04/20 8:29 pm
you can put larger rings in , you wouldn't be the first guy ,
but its not a magic solution .

once the bores get oversized ... they can really benefit from a Machinist
that can return the cylinders to a real geometric cylinder shape .
sometimes they didn't come from the factory cylindrical
... just within whatever tolerance was acceptable .

My old machinist , who is now retired , would show me
how are out of round my cylinders were ...
with the bores first pass as the base line . and they show/tell what he planned to do .
Posted By: Beach Re: Lighting no start - 07/04/20 8:48 pm
Originally Posted by Nick H
Rode the Lightning around the yard today. Clutch is easy and shifts without any effort or noise.
Had to oil the pistons for compression to start it though. Gasket seal is good but apparently I have leaks past the pistons and rings.
Or the valves still or both. New valves fit the guides better and the head held kerosene overnight, something the old valves didn't do.
Leakdown test was only slightly improved though. I could hear leaking past valves and inside case both.

The bores are 2.95" everywhere with little variation so my standard pistons and rings should be correct.
Ring gaps were .016"-.018". Would it help if I installed +.020" rings and gapped tighter?

Pleased to know my carbs, timing, wiring etc are good though. Big thrill to finally hear it fire up.
It's hard to get a correct measurement on the cylinders unless a somewhat experienced machinist. If your clearance was correct for std pistons, you wouldn't be losing compression and have too large end gap on rings. Just for a ballpark I'd put pistons in and push to one side and measure clearance with feeler gauge. Myself, I leave that part to the shop I use and save myself the heartache. You know all about that by now. Surprising how much one can learn with a battle like this.
Posted By: gavin eisler Re: Lighting no start - 07/04/20 9:18 pm
Cool bike,
first thing I noticed , bell mouths with mesh screens,
these screens do very little to clean the air, but they really mess up air flow, get rid , fit air filters, it will go faster, or lose the screens all together and leave the kilt for later, small rocks be damned. Thats why your bores are worn. Do not fit oversize rings, Ive tried, it ran, nothing really bad happened but it used a lot of oil. Big ring gaps are OK , if it runs be happy.
Posted By: Nick H Re: Lighting no start - 07/04/20 11:59 pm
It runs and I'm happy but it seems to take an oil bath to get started.

I'm thinking send the whole shebang to Michigan. Sure to be cheaper and better than local.

Thanks for tip about bell mouths. But they look cool! They are stuffed with hardware store air filter material.
I do have stock filters.
Posted By: gavin eisler Re: Lighting no start - 07/05/20 1:21 am
Once the back mudguard snaps off it will be time for a rebore.
Posted By: Nick H Re: Lighting no start - 07/05/20 1:25 pm
Originally Posted by gavin eisler
Once the back mudguard snaps off it will be time for a rebore.
Alright Gavin you want to clarify that comment for me?
Are you saying rear mudguards are prone to snap off?
Time for rebore is now!
Posted By: gavin eisler Re: Lighting no start - 07/05/20 3:16 pm
If the rear mudguard loop is absent, the mudguard cracks at the seat loop mounts.
Stand behind the bike while someone revs the motor up and down, the rear lamp can be observed going in and out of resonance like a rattlesnake tail. I agree , time for a rebore.
Posted By: Nick H Re: Lighting no start - 07/06/20 1:34 pm
Thanks, didn't realize I was missing a part.

I have read some posts where people have had the same type of piston clearance (.007 or so at the top) and ring gap (.018-.020) as I do and claim the bike runs fine which is why I proceeded with the assembly.

Is there any possiblity that some break in running time will improve the compression issue?
Posted By: gavin eisler Re: Lighting no start - 07/06/20 6:27 pm
There is an old time way to bed in rings, it involves adding some fine abrasive to the inlet, I forget the name of the US brand , in the UK its called scouring powder, used as a last resort.
Someone here did a write up on it , maybe not the BSA forum but some where here.
I have never tried it, and it does sound drastic, but the write up mentioned a surprising success.
One of the US members will know the correct brand name.
I presume the oil is dumped and refreshed immediately after to clear contaminants.

First maybe give it a few hundred miles , if its no better what have you got to lose?

look at some pics of your year model, the rear mudguard loop is a black tube with runs from the top shock mounts and pics up the rear guard at the tailight housing , your rear lamp is not stock, fear not the correct type is not rare and decent repops are out there, the original loop has a couple of additional tabs for the optional grab rail. its a pretty simple affair , a person with some steel and a welder could make a decent copy. or try ebay

If you want to stick with unfiltered air, a shorter bell with no mesh will work a lot better.
Posted By: Allan G Re: Lighting no start - 07/06/20 7:07 pm
One thing I’ve found with the shorter bell mouth is they are more susceptible to faltering when it rains, never had this issue with the long velocity stacks... only fun with tuning.
Posted By: Nick H Re: Lighting no start - 07/07/20 1:09 am
The powder is called Bon Ami. I've read about using it for break in.
It's soap and feldspar and they promote it as being good for cleaning vintage car windshields.

But I'm grasping at straws here. Compression is way low. Going for the rebore.
Posted By: BSA_WM20 Re: Lighting no start - 07/07/20 8:17 am
Bon Ami was the go for Vintage bikes in the day when they were new
Back then deglazing the bore & scraping the head were items of routine maintenance.
I would be very weary of doing it to a more modern engine
Posted By: Nick H Re: Lighting no start - 07/30/20 2:58 pm
Update.
Got the cylinder back from the pricey local machinist who did an .020 bore and hone. Ring gaps were .008"-.010", considerably tighter than before.
I assembled with just a smear of oil on the front of the pistons hoping for a quick break in. Well, cold compression was not improved. I'll have to do another leak down to see what's up but this was disheartening.
Bike would not start so I reverted to the old oil on the piston top trick again and this worked. I don't know what this will do to my ring break in process but I'm sure many here will have some ideas.
Bike is not legal so I blasted around the yard in first gear for a while. Hot compression went to 90.
That was yesterday. This morning I started the bike without adding oil to the pistons again. Just a tickle and 3 kicks.
I'm hoping it continues to start easily and compression improves with break in. I don't want to have to go for valve seat work. Head has new valves and springs and holds kerosene for a day or better.

By the way, Gavin's right. Tail light shakes like jello.
Posted By: Beach Re: Lighting no start - 07/30/20 3:26 pm
Your compression after rebore may not be much . Seat the rings in, then check the compression. I would almost bet your problem has finally been solved. Fingers crossed.
Posted By: Nick H Re: Lighting no start - 07/30/20 9:59 pm
So I decided to strobe the engine. Here is a photo showing my primitive markings.
The left mark at the pointer is TDC and the right mark (looks like a cross) is 34 degree BTDC.
[Linked Image from i.imgur.com]
While it was strobing at idle, the rotor appeared to be frozen at roughly the point it is now in this photo,
except that only the advance mark (cross) could be seen. I could not see the TDC mark at all.
This seems odd to me. Maybe someone can explain.

I have no tach, however as I increased engine speed as far as I dared I could see the timing advance nicely.
I was concerned about this as you may recall I used 2 strong springs on my advance unit.
Posted By: koan58 Re: Lighting no start - 07/30/20 10:17 pm
“While it was strobing at idle, the rotor appeared to be frozen at roughly the point it is now in this photo,
except that only the advance mark (cross) could be seen. I could not see the TDC mark at all.”

I’m not familiar with BSAs, but why would they set the pointer for TDC rather than the useful advanced timing position (say 34 BTDC)?
Posted By: NickL Re: Lighting no start - 07/30/20 10:34 pm
With a standard points plate assembly you should see around a 25 deg shift in the
mark on the alternator. Just make sure the fully advanced point is at 34 degs BTDC.
That's around 8mm or 5/16 at the piston. That can be tweaked to suit local conditions.
With wear and the 'high precision' assembly of the centrifugal parts, accuracy in
timing before the fully advanced point is somewhat questionable. See Hookes laws
for info regarding spring behaviour etc.
Posted By: koan58 Re: Lighting no start - 07/30/20 10:57 pm
So is the pointer/rotor line supposed to mean the same thing as it does on a Triumph (say for strobing)?
Posted By: NickL Re: Lighting no start - 07/30/20 11:21 pm
Yes, the line on the raised segment is the fully advanced mark.
It can be a bit confusing as there is the other hole in the cover
for the pointer, for the ET setup etc.
Just like the trumpet stuff, all lucas junk.
Posted By: koan58 Re: Lighting no start - 07/30/20 11:38 pm
Thanks Nick, that seems to be the most important thing to know!
Posted By: quinten Re: Lighting no start - 07/30/20 11:48 pm
Quote
While it was strobing at idle


Your timing marks won't line up at idle ...
Idle advance is approximately 14° B-TDC ... the engine never fires at TDC.
you can start the stobe at idle and as the RPMs increase ,
the "rotor mark" moves to the stationary-pointer and they will line up , or should line up ... at full advance .

full Advance would be ... 2500 to 3000 rpms... with points
and 5000 rpms with most analog transistor-box ignitions .
Posted By: Nick H Re: Lighting no start - 07/31/20 12:03 am
Y'all missed my question. I'll try again. While strobing, the advance mark I made that looks like a cross was visible and roughly in the photos position
at idle, however the TDC mark I could not see at all under strobe light. It became invisible.

It's odd because the strobe should just freeze the motion of the rotor, right? Should appear to be still so one can read "Lucas", etc.
It mostly does this but the TDC white paint mark with black line dissappears!

Don't be confused by my makeshift marks and pointer. Part of the case where the pointer is was cracked and I repaired with JB Weld. Made a pointer from a nail and painted on my marks.[i][/i] Rotor may be on backwards.
Posted By: koan58 Re: Lighting no start - 07/31/20 12:30 am
There never was a TDC mark on the rotor, it is a mark for fully advanced timing.
If you're lucky, there may be a TDC slot on the crank flywheel (like a Trumpet, with a hole behind the cylinders, I don't know that BSA provided such a convenience).

Get off the TDC trip. Why would one need to know TDC, when it is so simple to find it anyway?

In your post #818096

You show the pointer and rotor line aligning allegedly at tickover.

Except I don’t understand this comment:

“While it was strobing at idle, the rotor appeared to be frozen at roughly the point it is now in this photo,
except that only the advance mark (cross) could be seen. I could not see the TDC mark at all.”

So do you mean that the situation looked like this (with the pointer aligning with the rotor line) OR that the pointer aligned with the cross mark? Please be clear.
Please forget any idea of a TDC mark.

Just trying to get to the matter!
Posted By: NickL Re: Lighting no start - 07/31/20 1:41 am
The A65 should have a fully advanced ignition at around 2500rpm with the points setup.
This equals about 8mm or 5/16 BTDC = 34 Deg BTDC
The standard centrifugal advance setup will retard the ignition about 12 degs cam or 24 degs Crank.
SO, at idle you should be somewhere around 34 minus the centrifugal system figure (say 20 degs @1000rpm)=14 degs BTDC
Posted By: koan58 Re: Lighting no start - 07/31/20 3:46 am
very patient this evening Nick?
and a good evening to ya mate!
Posted By: Nick H Re: Lighting no start - 07/31/20 12:26 pm
Thanks, i understand the timing and the advance. Not asking about that.
I must have a problem getting my message across.
I like having the 34 degree advance mark and the TDC mark visible as a reference knowing that at idle the pointer will be a bit counter clockwise from TDC.
I suppose it would be smarter to make a mark at 10 degree BTDC (34 minus 24) where timing should be at idle but as I have been reminded several
times here it is the full advance point that is critical.
As NickL mentioned this is only a start point and many variables such gasoline used, carb setup,compression, altitude, etc., etc. will effect and determine the best points timing. Can I get an "Amen"?
Posted By: Allan G Re: Lighting no start - 07/31/20 1:08 pm
Originally Posted by Nick H
Y'all missed my question. I'll try again. While strobing, the advance mark I made that looks like a cross was visible and roughly in the photos position
at idle, however the TDC mark I could not see at all under strobe light. It became invisible.

It's odd because the strobe should just freeze the motion of the rotor, right? Should appear to be still so one can read "Lucas", etc.
It mostly does this but the TDC white paint mark with black line dissappears!

Don't be confused by my makeshift marks and pointer. Part of the case where the pointer is was cracked and I repaired with JB Weld. Made a pointer from a nail and painted on my marks.[i][/i] Rotor may be on backwards.


It’s not odd at all. The flash of the strobe is at the point where the spark happens. As the timing advance the sparks relation to the pointer moves. You just adjust the timing until the mark aligns where you intend it to be.
Posted By: Beach Re: Lighting no start - 07/31/20 1:23 pm
Originally Posted by Nick H
Thanks, i understand the timing and the advance. Not asking about that.
I must have a problem getting my message across.
I like having the 34 degree advance mark and the TDC mark visible as a reference knowing that at idle the pointer will be a bit counter clockwise from TDC.
I suppose it would be smarter to make a mark at 10 degree BTDC (34 minus 24) where timing should be at idle but as I have been reminded several
times here it is the full advance point that is critical.
As NickL mentioned this is only a start point and many variables such gasoline used, carb setup,compression, altitude, etc., etc. will effect and determine the best points timing. Can I get an "Amen"?
Looked back through this whole thing and looks like you're sure of timing marks being correct and it strobed at your mark. If all these thing are correct, why don't you just ride it and enjoy. If you're not sure of timing marks, use piston stop and degree wheel to verify.
Posted By: Allan G Re: Lighting no start - 07/31/20 1:36 pm
I’m curious about the red mark, it looks like it’s on the original factory mark.
Posted By: Nick H Re: Lighting no start - 07/31/20 3:39 pm
Originally Posted by Allan G
I’m curious about the red mark, it looks like it’s on the original factory mark.
Nope, that's a red marker of mine from when I was using a different reference on the stator.
Originally Posted by Beach
why don't you just ride it and enjoy..
Excellent advice!
Posted By: NickL Re: Lighting no start - 07/31/20 11:21 pm
Originally Posted by koan58
very patient this evening Nick?
and a good evening to ya mate!

Salutations, old chap, hope all is tickety boo.
Posted By: gavin eisler Re: Lighting no start - 08/01/20 2:21 pm
If you can read Lucas on the rotor is on the right way round.
There are NO TDC marks on the rotor as stock.
The correct alignment is the pointer freezes against the line on the raised pad at full advance , roughly 3, 000 rpms with points.
I know your flywheel is on wrong so the notch is no use.
However so long as the alternator rotor is fitted to its key way relative the crank the line on the raised pad is definitely 34 BTDC, the crank is separate from the flywheel.

If you assumed the line on the raised pad was TDC, then you have been chasing your tail with wildly off ignition timing, if the rotor is correctly fitted and your pointer is in the correct hole ( which it is, LHS is correct)
then your paint marks are completely unnecessary. Do you have a decent manual, ? this is all explained in the book.
Posted By: Nick H Re: Lighting no start - 08/01/20 10:15 pm
???
Do I have a decent manual? Now that's hitting below the belt, Gav.

My problem was COMPRESSION!

My BSA rotor does not have a raised pad like this one on my current Triumph project:
[Linked Image from i.imgur.com]
Here's another photo:
[Linked Image from i.imgur.com]
Don't know why it upsets people so that i mark off TDC.
Don't give a rat's ass if it's stock.
Gavin, you have been immensely helpful but give me some credit for brains will ya?
Posted By: gavin eisler Re: Lighting no start - 08/01/20 11:10 pm
OK , do yourself a favour, fit the correct type rotor, sorry if I insulted your intelligence. It should look like the triumph one, the crank key way puts it all right. Best of luck
Posted By: koan58 Re: Lighting no start - 08/01/20 11:41 pm
I can only guess that the rotor is an earlier one than would have originally come with the motor (what’s the purpose of a timing pointer without a timing line on the rotor?)

Did you ever check to see if the rotor is on backwards (as you suggested as a possibility)?

It’s difficult to tell from the angle of the photo, the advance mark is fully 34 deg before the TDC mark?
Posted By: gavin eisler Re: Lighting no start - 08/02/20 12:11 am
I agree with KOAN, if the T mark is TDC, the I mark does not look like 34 degrees before. More like 15 after.
How exactly are you establishing these marks.? Also the marks are arsey facey, the I mark should come before the T mark, the rotor rotates anti clockwise looking from the primary side . As shown in the pic the I mark will be after TDC. So far your brain credit is in the red. Wise up.
Posted By: Allan G Re: Lighting no start - 08/02/20 8:18 am
Nick, I think you over reacted to Gavins comment about the manual, so many will ask a question before reading the manual, I’ve even been guilty of that myself. If you read the manual and go through it properly there is little reason for anyone to ask most questions on the forum.

I could be wrong but I Believe the early rotors are thinner, you might want to check this as it might effect power output.

The above comments are also correct, the Fully Advanced Mark should be right of the TDC mark, as the crank turns in a forward motion it will spark before TDC is reached, as the crank rolls as if it was pushed forward on the ground, the mark right of TDC will reach the top before the other mark will.

If the magnet is good on the other rotor, fit that... otherwise buy a new one, it’ll save you a lot of headaches.

Also, if your timing light has an advance dial on the back, turn it fully left and glue it in position, some (least mine does) has the habit of moving too easily and you find the timing is way off when you have set it. A glue gun is ideal for the job wink
Posted By: Nick H Re: Lighting no start - 08/02/20 12:04 pm
Don't get me wrong, I'm grateful for the help I get here. That people would take time out of busy lives to help me out of the kindness of their hearts, I can't really fault them if them don't read my every word carefully and remember it (and they don't) , however, I did note that the mark on the left is the TDC. I created confusion by my advance mark looking like a "T".
I concede that the two marks do not look to be 34 degrees apart and this has troubled me. I have a printed degree wheel sized to the rotor and my piston height measurement conflicts. So I F'ed up somewhere.
I'll take Allan's advice and put on the other rotor and see where that timing mark lands me.

Are all rotors supposed to have an advance mark from the factory? I have a Sparx on my Triumph and it doesn't.
Also, don't T120's and A65's have different timing advance degrees?

Service manuals are free to download so everyone has access to them. Some things, like valve timing for example is barely mentioned in the manuals. They give the opening and closing points and suggest setting tappets at .015" for testing only. That's it! I didn't really catch the meaning of that until I asked here and I believe it was Gavin once again who spelled it out.

Anyway, it's all good and my starting problem was COMPRESSION (and timing)!
Posted By: Allan G Re: Lighting no start - 08/02/20 7:45 pm
The marks on the rotors came about the same time they put inspection windows on the primary covers, I think this was c1967. As all rotors with timing marks are made equally The factories had to either index the position on the primary case to suit alignment of the timing mark on the rotor. Another thing worth adding is that the early cranks with 2 sludge trap plugs, do not have the same key way position on the crank as the later cranks, why bsa couldn’t have kept this the same and used a different position for the pointer is anyone’s guess, however they didn’t and if using an early crank this part needs to be made aware of.
Posted By: quinten Re: Lighting no start - 08/02/20 11:07 pm
allen covered this , so mostly saying the same thing in a different way

Quote
Are all rotors supposed to have an advance mark from the factory? I have a Sparx on my Triumph and it doesn't.
Also, don't T120's and A65's have different timing advance degrees?


a rotor can go on either way , but only one face is usually marked .
early rotors had no mark ... later ones had 1 mark ... and the last ones have 2 marks , 180° apart .
but these are not timing marks
they are .... Centerline of the rotor-keyway marks .

its the crankshaft and its corresponding rotor- keyway
that has ... a degree angle ... to the cranks TDC

the rotor is a generic part that can transfer the ...crankshaft keyway slot .. to a readable line
on the face of the rotor . .. the same rotor will work with various timings of a BSA , Triumph or Norton

The primary cover holds the last part of the timing information .
with no cover ... the rotor mark has no reference .
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