I just purchased a new motor for my MST-1. I used all the hardware Mugen included in the box. I put on the collet and flywheel to get an idea of how much thread I needed to cut off. I then took my dremel and cul off the extra threads (with collet and flywheel off). I then put collet, flywheel, washer then Mugen clutch nut on. I also used a little locktite on the threads before putting the clutch nut on. Then you can follow the manual on putting on the clutch bell and shoes.
Yokomo YZ-2, B-Max4 III
Losi 22b, XX4 Worlds
Associated SC10.2, RC10B2, RC10T2, RC10