I just rebuilt my gx200 clone with a few modifications. I put a hot 265 cam in, billet rod, billet flywheel, jetted the carb with a k&n air filter, and a racing pipe on the exhaust. It misses pretty bad especially at top end, and I can only open the throttle to about 1/4 to 1/2 or it hardly runs. I set the valve lash by feel and didn't measure the clearance, and I didn't do anything to the ignition coils clearance. Could these be what is causing it, or could the jet be to big, or could it be the ignition coil? I just want it to run great and have smooth acceleration when I hit the throttle.