Here's the deal. I can't split my cases because I had to weld the crankshaft gear to the crank. (long story) Anyways, this engine runs very well but has severe vibration towards the higher RPM range. So, let's say I pull the jug and piston and have access to the crank counter weights. I was thinking of drilling out some material on the crank pin side of the counterweights. Doing this purely as guess work, what do you think the result might be? I know this is completely unorthodox, but the vibes keep me at about 15 mph or so. If I am consevative on the drilling, it might improve assuming that is where the weight needs to be reduced. Call me crazy.