I have an 83' cr125, and wanna squish all the oomph out of it that I can. I need a shift drum to complete the engine. But here is what I'm doing. New larger front sprocket, new racing crank,tuned expansion chamber, bearings, rod. and finally, shaving the head to raise compression. the question? Will shaving the head #1 ruin the power band or increase it? and #2 will adding octane booster damage the engine? let me know. -Colt :think: