Hi I have been working on my son’s Rally (again). The problem was it jumped time, couldn’t find anything else wrong with it other then to replace the timing chain, camshaft gear etc. I don’t think it hurt the values any.

Anyhow I got to thinking about TDC crank and camshaft timing and ignition timing. What I was wondering is do these ATV typically do a dual-fire? That is do they also fire the plug on the exhaust stroke? The Rally uses an Inductive Discharge Ignition per the shop manual. The Magneto Flywheel has one protrusion that works with the trigger coil. So as I was thinking about this I thought that it has to fire on each stroke, including the exhaust stroke, (although it would not have any effect). Since the protrusion would fire it on each revolution of the crank. Then I got to thinking that maybe most single cylinder 4-stroke engines do this and I never really thought about it, obviously makes the ignition simpler.

Anyhow I think we got everything locked down where it belongs, but if the ignition fires on every “stroke” as long as the piston is locked at TDC and the Cam-shaft also, all is well, the ignition timing doesn’t really matter if it fires on each stroke? Any thoughts?