Sometimes when I am accelerating in the lower gears my drivetrain feels like it is jumping over a sprocket tooth. I think that is probably impossible with a properly adjusted belt but I have no other idea what might really be happening. It has an after market clutch in it and I could see that slipping but not making the kind of jerky, jumpy moves this thing is making. It only does it once or twice real quick and then it's OK.

The bike is a 1988 FXR with an 89 clutch assembly in it. Please advise.