sparky01
XS650 Enthusiast
Just rebuilt my 81-650 with a new big fin cylinder, new timing chain and at idle you crack the throttle it back fires through the exhaust (2 into 1). As you let the clutch out and give it gas it stumbles and misses until about 1/4 throttle and then it runs fine. When I was installing the timing chain at tdc the mark on the cam was off 2 degrees from being straight up. I put the mark slightly towards the front of the motor as the timing chain stretches it should be straight up. I am running a set of carbs (2 cycle) from 650 central, can this be the problem. Running new stock head from hoots racing. Compression is 135-135, as rings are not seated all the way in. I am frustrated and need some HELP.