I recently got my '74 Suzuki TS250 running. New top end, new lots of stuff. It runs great. Very quick. Lots of torque. One problem. When the engine gets to running temperature the idle won't come down all the way and instead stays very high. The throttle cable is new, slides freely and doesn't seem to be crimped anywhere. The carb slide appears to be coming all the way down, the air screw is at one and a half turns out. The idle screw is retracted all the way, but the idle stays up. It seems this must be a carb issue, but I'm out of adjustments to make. For what it is worth, the carb is not original. Original was 28mm, my carb is a 32mm. It still should adjust down, though. Suggestions?