78 xs 400 it has been great with the exception of the stalling



every time i start the bike after it has sat overnight the cylinder on the right side(if you were on) the bike fires right away the cylinder on the left i get unburned fuel out of the pipe and the occasional pop and after revving the right cylinder for a lil bit the left cylinder starts to fire normal...



when the bike is cold it will idle perfect,however when it gets to operating temp..it will intermittently miss at idle and in extreme cases when i come to a stop light if i let the rpms drop to idle it will immediatley stall but does usually start back up... so i have been riding it and just keeping the rpms up at stops but i want to get it straightened out



with the info i have it seems as if it is losing spark on one cylinder but my question is what component would cause this ??

any help is appreciated...thanks ...dave

 

Sounds like the left carb is having issues. It might be a good move to rebuild and sync them. I think that only uses one coil, and fires both plugs at the same time as a waste spark system.

 

Try switching plug wires and see if it moves to the other side.

It's rare to see too much fuel unless a float valve was leaking, and then it would flood with the engine off.

I had an RD 400 of similar vintage that would do the same thing.