Reply To: Backfire/misfire thru carb

[billw]

Those V4s will sneeze at the drop of a hat, if everything isn’t right, for sure. Fleetwin is right (as usual, of course) in starting with a careful link and synch. Next step in my book would be a thorough carb cleaning. IF those two things don’t cure the problem, I guess I would start looking for a leaking crank case sealing job, from the rebuild….

I think the answer to the original, theoretical question, is that when there is a back fire event in the crank case, it takes a few fractions of a second for the reeds to close and stop the backfire, so you will see a bit of a blow-back out the carb. Be thankful for the reeds. If you had a rotary valve engine, you’d have a good chance of seeing flames come out.

Long live American manufacturing!