I had a failure on the front cyl throttle shaft yesterday.now i thought this problem was limited to the 58mm bore shafts but no.mine are still the standard 53mm bores but running stage two cams with powerline exh.firstly, i had a cracked head then this and am wondering weather these cams are worth the unreliability i am experiencing with this motor. i have over 50000km on these cams and 70000+ on the motor,not nearly enough to call it wear and tear.Are others out there having failures also with the standard shafts/ 53mm bores?