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Re: Lighting no start
Nick H #813145 06/19/20 1:19 pm
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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?


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Re: Lighting no start
Nick H #813151 06/19/20 2:16 pm
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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.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Lighting no start
Nick H #813185 06/19/20 6:51 pm
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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!

Last edited by Nick H; 06/19/20 6:52 pm.

1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #813188 06/19/20 6:59 pm
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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


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Re: Lighting no start
Nick H #813195 06/19/20 7:22 pm
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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.

Last edited by Nick H; 06/19/20 7:27 pm.

1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #813201 06/19/20 8:18 pm
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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


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Re: Lighting no start
Nick H #813204 06/19/20 8:45 pm
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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.

Last edited by gunner; 06/19/20 8:47 pm.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: Lighting no start
Nick H #813234 06/20/20 2:06 am
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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


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
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Re: Lighting no start
Nick H #813337 06/20/20 11:43 pm
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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?!

Last edited by Nick H; 06/21/20 4:22 pm.

1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #813989 06/25/20 8:36 pm
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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?


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #813991 06/25/20 9:07 pm
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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/

Last edited by gunner; 06/26/20 8:05 am.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
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Re: Lighting no start
Nick H #814038 06/26/20 6:13 am
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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.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Lighting no start
Nick H #814150 06/27/20 2:04 am
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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.

Re: Lighting no start
Nick H #814201 06/27/20 3:03 pm
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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.


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #814230 06/27/20 9:56 pm
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i would ride that around just to annoy people


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Re: Lighting no start
Nick H #814242 06/28/20 12:32 am
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Ha! I should. It's loud as hell!


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #814828 07/02/20 10:12 pm
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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!!!!


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
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Re: Lighting no start
Nick H #814830 07/02/20 10:38 pm
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Well done smile


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: Lighting no start
Nick H #814848 07/03/20 3:09 am
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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.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
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Everything will be alright in the end. If its not alright, its not the end.
Re: Lighting no start
htown #814856 07/03/20 6:43 am
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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.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Lighting no start
Allan G #814877 07/03/20 2:06 pm
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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%.


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
Re: Lighting no start
Nick H #814913 07/03/20 7:22 pm
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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.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Re: Lighting no start
Nick H #814917 07/03/20 8:13 pm
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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


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
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Re: Lighting no start
Ignoramus #814924 07/03/20 9:08 pm
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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

Re: Lighting no start
Nick H #815017 07/04/20 12:44 pm
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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).


1966 BSA Lightning
(2) 1967 Triumph "Choppa"s
1974 Indian ME125
1960 Harley Servi-Car
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