i have raced a force 12, i had 2 engine failures in 2 months, just 4 race meets. firstly, front bearing failure, destroyed piston and sleeve. second, crankshaft faiure, pin on end of pullstart somehow broke, not when starting it either, mid race. i had it replaced, but 2 failures costly to points. i was mainly running around 5th to 6th, with the force, never run engine above 230f max. guys at front were all os 12cvx, i have switched this season to the OS. less moving parts in pullstart, easier tuning, and now setting the pace, 5 points clear of second place, and TQ every round. go the OS.