just ran my CRF with a new collet instaleld with jb weld.
i've found the engine definately needs to be geared down from the pinions. i went down 1 tooth for each pinion from the normally used pinions at my track.
gear it down (from the pinions) and loosen the two speed ( went out 1.5 turns from my max MF tuned 2 speed settings). this engine definately needs to rev alot.
the top speed was very impressive
, even with the lowered gears, (which seems to be the case with most engines now-adays maybe except for the JL red dot). The driving style on the throttle seemed to require a more aggressive approach also, but maybe this was just my impression.
overall, in my opinion only, the engine requires a closer attention paid to tuning it (read possibly harder to tune...i found it tricky anyway), and requires the user to reduce gearing as well. My engine when it entered the pits idled fairly high but the tune was consistent throughout the race final (1/2hr)