ok so i am fixing a ds650 for a customer right now and i was wondering if someone could help me with what jets are supposed to be in it. it has a ron woods intake and exhaust, i believe the engine is stock and i think the carb is stock, it has a single mikuni. ok well anyways it has a horrible stumble off of idle and i believe it is the pilot jet, so i went and got the next size up and that didnt change the way it ran at all. any suggestion please let me know

 

I would try dropping the needle a bit and see what happens sounds like it might be raised to high and putting to much fuel to quick to the motor. Also adjust your air fuel mixture screw both of these should help.

 

Agreed I would do the same... What are the colors of your plugs?