I posted this in the two stroke forum, silly me. With 3750 clutch springs and 18.75:1 final gearing, I can load the engine easily. Going WOT under heavy load causes a pulse back through the carb, spiting fuel into the air filter. The carb is good, exhaust port & muffler are clean and the compression is good. The bike runs great except for this problem. Has anyone run into this before.