Engine bearings
A little off the subject but, Aren't ceramic bearings illegal for use in ROAR racing?
Anyway I'v had bearing problems with my Top engine too. There is no engine that is immune from bearing problems. I had 2 bearing failures in my top and both seemed to stem from the seal coming off and letting dirt into the bearing making it wear very fast. The third braing I smeared RTV around the edge of the bearing making sure to get some on the seal and have not had a problem since. That engine finally expired at 8 gallons and I have done the same thing to my new moter (Rex) basically then same 421B. I've got 2 gallons through it and no problems yet.