How much can I take off the base of an 066 jug to increase compression, but not affect the timing? Also, does anyone know off-hand what size the major threads are in the flywheel?
None. Any material removed from the base will move the ports down the same amount. To compensate for this tuners regrind the ports to raise them back up. If you cut the base to a safe squish clearance number and do not touch the ports your 066 will be a torque monster, because the powerband will be shifted to a lower peak rpm. You will probaly lose cutting speed though as the rpms will be lower as will chain speed.
