ok here we go i have cen matrix - venom starter box - novarossi 21bf. The problem i am having is the cen flywheel will not reach the starter box wheel. I switched the flywheel with another off a hyper 7 which is much bigger but the problem is it hits the brakes it is to big. So i am back to the cen flywheel which is too short for the box. Does anyone know the solution to my problem.

I'm having the same problem, and it's really pissing me off. I'm almost ready to say "screw Nitro" and Ebay my matrix for a mini, or a helicopter or something. A hobby should be fun, and not a pain in the _ss!!

I have the matrix RTR with an OS.21 VG, and my fly wheel seems like it should be lower to the chassis. Is there another motor mount or fly wheel that anyone can recommend? Or is the car designed to only be used with pullstart engines?

I filed the sides of the opening on the chassis at an angle, helped a lot.

Yep i had to file mine also, but also on my box i had to remove all of the risers on the starter box.