thanks for the reply its going in my tnx and the only way i can access the engine is thru rotostart. i found some tips in savage central and found that there is no rotostart package for the sirio, but i can build up one from parts: hpi .21/.25 rotostart case, gear set backplate unit (for the larger 8mm id 1-way bearing), and towerhobbies st15 1-way bearing and hex ive read that this will work fine, hope it does for me cant wait to fire up this baby, my tnx's first italian motor