2001 660 intermittent 1/4 throttle sputter
I have a 01 660r. Rode fine the first day I bought it then the next day it sputters at 1/4 throttle the revs fine after you muscle past that but only when you let the clutch out! Revs fine in neutral. I took it to the dealer and they told me it needed a top and bottom end. I went with the 719 stroker kit and when they had it finished i went to pick it up and it has the same problem. It is intermittent. Sometimes it rides great for awhile the back to it. It has the reverse rev limiter bypass and I have checked and redone the wire. It blows a little black smoke while sputtering. Carbs were gone thru multiple time by them and me. I'm at a loss any advise is appreciated.