gx200 missing

[Storm200minibike]

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.

 

[Strigoi]

You need to use feeler gauges when setting the valve lash. You can't set it to thousandths of an inch by feel . It's a good idea to set the coil gap as well. You can open it up some with the billet flywheel since they have a stronger magnet. If you look around online you can see what people like to run it at.

It sounds like you have a jetting issue. Is it a stock style carb? I'm running a hot .265 cam in one of my engines and it loves the 24mm Mikuni flat slide carb I have on it.

 

[panchothedog]

You need to set your valves at .003" . Set your coil gap to .040 to .045" and if you are running a stock style carburetor it needs to be rejetted. Probably up to around a #37 or #38 jet. It could be starving for fuel if you never changed the jet after installing the air filter and pipe. Anybody who says that they set the valves by feel obviously doesn't own a feeler gage so go to the auto parts store and buy one. The settings for the valves and coil gap are critical.​