I have a 3.1c.i. (51cc) Sachs chainsaw conversion that I am having problems with. It seems to run pretty good, but is missing quite often. It only happens at mid to high throttle. I have a CH ignition with synchrospark. I am also having a problem with it loading up and dying when I advance the throttle from an idle. I have leaned out the low needle but it doesn't seem to help. If I keep it around 3K and above it does not have a problem, but if I let it idle for more than 3 seconds it will not transition. Any pointers? It was only swinging a 21x10 at 6200rpm. I later tried a 20x6 that a friend had. It was turning 8400rpm. I was thinking it should have turned the 21x10 much higher.