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Ignition timing


I have just completed my Commando rebuild with Boyer ignition, Alton Electric start and Mikuni single carb.  The bike started first touch.  Tried to dynamical time it today and despite retarding the timing as far back I can it is still showing it is too advanced at 35 degrees compared with 31 which is in the Boyer instructions at 5000 rpm. The issue seems to me to be that with only one location spigot on the Alton chain case the timing arc on the chain case can be changed significantly as the chain case rocks up and down. Has anyone else found that they can’t retard the ignition enough?  I suspect the timing arc to be at fault as the bike doesn’t pink if accelerated from leg revs


I'm not familiar with the components you're using. But surely, if you need to retard/advance the ignition more than rotating the pickup plate slots will allow, you just pull the rotor out from the end of the camshaft and replace it a little further round (which ever way you need to go).

It's worth noting that you can't really rely on the timing marks on the alternator rotor and primary chaincase until you've checked them using a timing disc from TDC.


Well said Stan all good. You do not need to mess with chain cases or spigot. Check/confirm the timing plate via TDC first. Then consider moving the rotor.


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