I just rebuilt my evo and upon first attempt of start up it cranks.....kicks and bang! Backfire from front cyl.....I'm going to put #1 at TDC and check for timing mark if its ok do I have to do the same for rear cyl or what should I ch next??? Please help!

 

Do you have adjustable pushrods? If so check their adjustment.

 

Timing: Firing to early or to late through an open valve.
Valve adjustment to tight: firing through an open valve.

 

coil wires backwards

 

Timing , I've had a pushrod go loose and make a hell of a backfire.

 

Hahahah thanks to all!!!!!!! Ya got it all fixed up!! Checked all the in depth stuff and ya it was the coil wires backwards!!!!!!! Lol what an idiot!! Well I was pretty sure I did everything the right way but a couple beers when getting ready to fire and over looked the obvious! Thanks and ride on!!!!!

 

purdie, did the same thing after building my evo

loud, eh? ...lol

 

If both spark plugs are plugged into the same coil, then they are both firing at the same time. That is the stock Harley ign. system. If you have an aftermarket single fire system, then you will have 2 seperate coils in order to fire the plugs independently.

 

Your funny ...................