last night i went to assemble the crank again and noticed the big end of the rod is trashed and the stock bearing had 6 cracks in one side of the cage. so i pressed apart a spare crank that had the same long rod, same problem only not as pronounced, this rod was only uned in a stock motor for a little while. these latest developments mean that i will never use that za rod again. i have one other 3.8mm shorter rod that i didn't want to use because of it's shortness, but it does have one redeeming feature, the big bearing is uncaged rollers with thrust washers. so i assembled the crank with the shorter rod and trued it to .003" . then i filled the area where i removed material in the balance pads with silicone, (to bump up my primary compression) and bolted them on the flywheels. since i used the shorter rod i will have to remove 3.8mm from my 7mm cylinder spacer, (which will also bump primary compression).
john,
i would machine the head if i needed to change compression, since the cylinders cost so much. the hi comp head from treatland works pretty good
baird,
i had a blowout at about 40 once and it was pretty scary. i don't mind the fall as much as getting run over.