BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: Fereday on 02 April, 2017, 18:08:21

Title: Pre ignition
Post by: Fereday on 02 April, 2017, 18:08:21
Hi there gave the bike a run for the first time took up and down the dual carriage way for a shake down noticed battery acid all over exhaust and to make me feel better the bike tried to start after switching off I've had electronic ignition fitted the bikes a thunderbolt
Title: Re: Pre ignition
Post by: Fereday on 02 April, 2017, 21:23:35
Have checked the acid level on battery and found that its been filled to the top could this have caused the pre ignition
Title: Re: Pre ignition
Post by: Bess on 03 April, 2017, 07:16:10
    Acid level will not be a factor.

I believe you have had electronic ignition fitted recently. If I have issues I always migrate to the last item altered, so I would suggest the timing is too far advanced.

If you list all the things you have changed recently and the circumstances of the issues, this forum can help further with a solution.

Best wishes.....
Title: Re: Pre ignition
Post by: SLIPPERY SAM on 14 April, 2017, 13:05:14
I agree with Bess.
If it didn't do it before you touched something (in this case the electronic ignition) - then it has to be something you did.  Triple check the ignition settings - try a different method to before, use a degree wheel? find TDC/timing mark differently, there is a choice of methods and things like different pistons can throw out the 'distance piece' in the plug hole method of finding the timing angle.
For the battery acid - sure over filled isn't great - but could be over charging and boiling the battery.  I'd recommend checking the Reg/Rec (happened to me once on a Slimline Commando - zenor diode unit packed in but instead of not charging it decided to boil the battery - oh and that was the week after I fitted Boyer electronic ignition!!!).
Is there more to the story?
Title: Re: Pre ignition
Post by: RICHARD MILLS on 14 April, 2017, 18:29:02
You can trigger a spark on a Boyer ignition system by the act of switching the ignition off.