Teflon inserts for crank bearings

[dirtbike]

As far as I understand, had all 495 works engines conventional ball bearings as crank bearings instead of the magneto M-30 bearing. These bearings where mounted in the cases with a teflon, or plastic insert.

We have a few number of possible reasons for why they did this. Does anybody in here know for a fact why they had this configuration in their works engines?

[brian kirby]

Rotax had the same inserts in all their engines. It allows the metal cases and bearing expand and contract, but keeps the bearing tight to keep it from spinning in the cases. It also allows you you press in/out the crank without using any special tools. I assume that is the same reason KTM would do it.

Brian