I'd also be interested in knowing this. On my 2-stroke edger engined cart which I'm almost finished I have just replaced the spring throttle with a solid wire and it sounds like its going about 6000 RPM, it has a cast iron block.
You want to remove the gearing because of the increased speed. You don't want stuff flying apart inside your engine, especially the two weights inside the plastic gear.
can you say boom!! if your going to do this make sure take off all parts that could cause problem. This would also be a great time to upgrade the cam,piston,rod,crank all that could break.I've had mine off for a few week and nothing has happen yet.
how hard would you have to rev it for how long to crack the piston or something.. i plan on just hooking up my throttle to the carb and trying to not go too hard on it.