I am having problems with my chopper again. I have a 99 evo motor that starts stalling on me around 20-30 min into my ride. It doesn't die on me or cut off and it idles just fine, it just starts spitting, backfiring and stalling on me. It has a brand new ignition module, new spark plugs, new plug wires, all of the other electrical components are working fine, battery terminals are tight. I know the bike isn't getting overheated because it starts before the bike is at its full operating temperature. Any ideas on what it could be? I appreciate any help.

 

is the gas cap vent blocked? if it is not enough air is being let into the tank to let more than a trickle of fuel flow. next time it happens, remove the gas cap and see if it cures the problem.

 

Do you know when the intake manifold gaskets were last changed? If not that is where I would start.