Bob, I would try an orange cam, may be better for a 4 speed car. Timing sounds about right, 34°-36° total is around what Clevelands like, even in race applications. I would stay away from the 50cc pumps, way too big for a 650. The guy that built mine only used 30cc pumps, and it flows around 870 CFM. To me it sounds like not enough fuel right off the bat. Mine has no hesitation anywhere. My intake has a 1500-7000 RPM range, and you know how big the cam is.