Britbike forum

ignition timing?

Posted By: Dave Martin

ignition timing? - 02/02/19 8:51 pm

Ok, "finished" the rebuild. 1968 ish B44. new valves, guides, rebore (so new piston and rings) whole load of head problems (previous posts) but now well sorted.
New Wassell ignition plus Podtronics reg. New Amal carb. Ignition set up to the marks, which I have checked (9/32" BTDC as per Rupert Ratio). I kick and I kick ( tickle the carb, bring it up to TDC, ease it over with the deco ever, then kick like hell) but all I get is a "chuff" back through the carb. I stripped it back down to check valve timing marks, perfect, noticed one of the cam followers was wrong way round (Ah, ha THATS the problem) put it all back together...……. Kick, chuff , kick chuff. no darn different. It sparks real well, I put an electric drill on the crank shaft nut and spun the engine over (plug out), lots of sparks, so figured to put a strobe on it while doing that to find out WHEN it is sparking, BUT the only strobes available are " not suitable for motorcycles or vehicles with positive earth", so that would be me then. Does ANYONE have any ideas??
Posted By: kommando

Re: ignition timing? - 02/02/19 9:05 pm

Every strobe I have bought has worked on both types of earth.
Posted By: DMadigan

Re: ignition timing? - 02/02/19 9:06 pm

You can statically check timing by replacing the coil with a 12 volt (6?) lamp. Very obvious when the points open.
My strobe has a clamp for the plug wire and battery terminals. Ground polarity does not matter.
Posted By: Dave Martin

Re: ignition timing? - 02/02/19 9:37 pm

I hesitated to buy the strobe as that is what it specifically said on the box! would use a bulb to "check points open", unfortunately no points!
Posted By: Shane in Oz

Re: ignition timing? - 02/02/19 9:51 pm

"Near enough" ignition timing will normally be enough to get a bike running if everything else is right, then the timing can be set with the timing light.

BSA singles can be an acquired art to start, especially if they don't have a choke.
Have you tried pouring a small amount of fuel down the spark plug hole?
Does the spark plug look wet or dry after the start attempt?
What's the compression reading?
Are you opening the throttle when kicking?

My B44 starts cold quite readily with the throttle closed, but quite often floods when it's hot. If it doesn't show any sign of life in about 4 kicks, I give it full throttle which normally does the trick. Yours will probably be different, but that might happen to work.

People tend to discount the use of a Colortune because they can't be used at larger throttle openings, but they're extremely useful for this sort of situation. You can see what's happening in the combustion chamber (spark, flame colour, lack of flame, etc)
Posted By: Dave Martin

Re: ignition timing? - 02/02/19 9:59 pm

compression 120psi, valve gaps set correctly. plug looks wet. throttle closed. I agree on the "near enough" idea but how the heck do I get it "near enough" statically with electronic ignition??? I have no clue as to when it is actually firing as opposed to when it should be firing!
Posted By: Shane in Oz

Re: ignition timing? - 02/02/19 10:46 pm

That is rather a limitation of electronic ignitions. The instructions should specify the initial "near enough" static setting, but that doesn't help if there's a manufacturing problem.
I'm not even slightly familia with the Wassell units, but as a rule the trigger point is when the rotor magnet passes under the stator coil. You could set it slightly advanced from that and then fiddle around advancing / retarding until it shows some sign of life.

Your electric drill / timing light approach would be easier. You should be able to run yours off an external battery. They don't really care *where* they get power from, it's just to power the strobe light which is triggered by the high tension pulse to the spark plug,
Posted By: bodine031

Re: ignition timing? - 02/02/19 10:56 pm

Hook the lite to a battery not attached to the bike, it's just a power source for the light. the clamp on the sparkler lead triggers the lite. it sounds like the timing is off. but you have verified the pinion gear marks are lined up, so not sure. Make sure the push rods are in the right tappet. inne is outee intake is in the outboard tappet
Posted By: quinten

Re: ignition timing? - 02/02/19 11:49 pm

Wassel / Vape ignition .

A simple check is to change/ reverse the polarity
From the timing stator to the transistor box .
... if it's backwards ... the instruction sheet says
Timing will be retarded .
.
Posted By: LarryLebel

Re: ignition timing? - 02/03/19 12:48 am

About all I can offer is encouragement. I've had Wassell EI in my B44R for a few years now and I'm very happy with it. My bike is a one kick starter (with tickling) when cold and one when hot. I didn't have any installation issues that I recall. It fired right up and I adjusted the timing with my strobe light.
Posted By: Dave Martin

Re: ignition timing? - 02/03/19 1:25 am

Hmmm, just read the wassell instructions again again again, and noticed " The coil current should drop to zero after 2 seconds without triggering". Measuring with my multimeter all I am getting is 0.4mv across the coil???? any electricians out there ???
Posted By: Dave Martin

Re: ignition timing? - 02/03/19 2:33 am

do you mean rotate the motor BACKWARDS? surely that would give the "fully advanced" timing mark? If so, I have already done that but with a micrometer.
Posted By: quinten

Re: ignition timing? - 02/03/19 2:47 am

Originally Posted by Dave Martin
do you mean rotate the motor BACKWARDS? surely that would give the "fully advanced" timing mark? If so, I have already done that but with a micrometer.


No .
The transistor boxes timing is responding to the rotational Direction
of the camshaft or the idler pulley
That the little magnetic rotor is attached to .
As the kit is somewhat Universal
Some installation expertise is expected .
It's not that you haven't obeyed the instructions ... but we as non-participants
In the installation ... have to ask all the silly and basic questions
Posted By: Mark Z

Re: ignition timing? - 02/03/19 3:47 am

Is "near enough" accomplished with a Wassell as with a Boyer or Pazon, i.e., position the crank to the full advance point and line up the hole in the stator plate with the white dot on the magnet rotor?
Posted By: Dave Martin

Re: ignition timing? - 02/03/19 3:51 am

yeah, got you about the backlash. I rotated the crank back a good way from TDC then forwards again till I got to the 8mm before TDC. Both crank and cam "shaft" are counter clockwise rotation. I am happy to have "all the silly and basic questions" asked as I feel that I have done something silly and basic! NickL …. I get what you say about the few millivolts but what I was saying was, that is ALL I am getting, even when I first turn on. Then it begs the question as to why I get any spark at all, so you are probably right. must get a strobe on it to find out what is happening.
Posted By: Dave Martin

Re: ignition timing? - 02/03/19 6:57 pm

Oh my giddy Aunt!!! It starts! first time, every time! I had a niggling memory of a youtube vid of an old guy (a good 5 years younger than me!) starting his B44 real easy. he mentioned that he had got his method from this forum. I found it! Kick up to compression, valve lift over, continue till you feel the exhaust valve springs, re cock the kicker and kick! viola it starts! EVERY DARN TIME! Thank you every one for all your help and suggestion, as I said earlier in this thread "I was probably doing something silly and stupid". will still put the strobe on it to check timing, but hey, the relief!
Posted By: Allan Gill

Re: ignition timing? - 02/03/19 7:33 pm

I’ve found it’s all about the leg with these singles. I don’t like using the decompressor though, I take it up to compression, then rest my foot on the lever (not push) the crank will edge over compression then when it starts to feel free’r. Repostion the kick start lever and a strong but steady kick. These don’t like to be kicked like a 2 stroke, it’ll never start like that.
Posted By: Dave Martin

Re: ignition timing? - 02/03/19 8:21 pm

Two stroke?, two stroke!!?? I am surprised that you have not been expelled for even thinking those words let alone mentioning them on this forum!! one of my sons once bought one of them, it was several years till we spoke again. …… I must admit, I was unhappy with the way it "felt" when kicking but it has literally been over 40 years since I owned a British single and memories and techniques fade.....thankfully, as the last one was an old (even then) ES2 and it scared the willys out of me starting that beast! Since then it has been a long catalogue of machines from the orient, some even with electric start! This project was a "gift" from afore mentioned son by way of penance. Looks quite nice, made it into a kinda replica of an Enduro, fear not purists, frame and engine numbers do not match, it was a Bitsa long before I got it. Now the NEXT one ………… (don't tell the wife!)
Posted By: bodine031

Re: ignition timing? - 02/04/19 2:44 pm

Tip you may or not know. First start attempt after bike has sat. engage 1st gear hold clutch lever to grip and rock the bike back and forth till you feel the stuck clutch plates break loose. Makes it easier to start, also use Ford ATF the old [***] or primary oil for a big twin HD the old [***] also in the primary chain case.
Glad you got it running it is a big fun bike. I have a 69 B-44VS since the early 80's. Podtronics reg/rect, gel electrolyte battery( takes vibration better) Boyer Ign., Kuni 30mm roundslide. Make sure the battery you have is fully charged before trying to start, if its kicks back cause of low voltage it can wipe out the kickstart shaft/gear.
Posted By: Andy Higham

Re: ignition timing? - 02/04/19 4:30 pm

Originally Posted by Dave Martin
Two stroke?, two stroke!!?? I am surprised that you have not been expelled for even thinking those words let alone mentioning them on this forum!! one of my sons once bought one of them, it was several years till we spoke again. …… I must admit, I was unhappy with the way it "felt" when kicking but it has literally been over 40 years since I owned a British single and memories and techniques fade.....thankfully, as the last one was an old (even then) ES2 and it scared the willys out of me starting that beast! Since then it has been a long catalogue of machines from the orient, some even with electric start! This project was a "gift" from afore mentioned son by way of penance. Looks quite nice, made it into a kinda replica of an Enduro, fear not purists, frame and engine numbers do not match, it was a Bitsa long before I got it. Now the NEXT one ………… (don't tell the wife!)



OI !!
I love my 2 stroke Greeves. 38BHP @ 11,500RPM and weighs half of fukc all
Posted By: Mark Z

Re: ignition timing? - 02/05/19 2:35 am

Originally Posted by Dave Martin
Two stroke?, two stroke!!?? I am surprised that you have not been expelled for even thinking those words let alone mentioning them on this forum!!


I'm not a fan of two stroke engines either, but let's not forget that BSA earned its reputation as "The Most Popular Motorcycle in the World" largely on the success of the Bantam. So we must at least tolerate if not respect "two-smokers" on this forum.
Posted By: Allan Gill

Re: ignition timing? - 02/05/19 11:05 pm

Originally Posted by Dave Martin
Two stroke?, two stroke!!?? I am surprised that you have not been expelled for even thinking those words let alone mentioning them on this forum!!


Bit difficult really to be expelled on this forum, however the 2 stroke bantam was the most popular selling model group BSA built, probably because of its model run period as opposed to volume per year sold... maybe that’s why the factory thought it a great idea to produce the Ariel 3...
© 2019 Britbike forum