I've replaced stock exhaust with NHRC unit (great build quality, fit and finish) and modified air intake for improved flow (air intake pipe and Uni pod filter tucked inside modded factory airbox. EPA crap removed and vent/overflow hoses rerouted. Stock jets are 110 main and 35 pilot. Parts seller (Scootertronics) supplied 130 main and 45 pilot. Ran like crap!! I talked to a local bike shop where I've dealt for years. They suggested a 117.5 main and 40 pilot. Runs much better, but no improved top speed at WOT. Also some mild popping on decelleration/throttle overrun. I read that lean bottom end can not be improved with jet alone, that some passage in the carb needs to be drilled. Anyone have more info on this?? ( Sigma 6 kits any good??)
