I was going to remove the rear NU209 main bearing on the engine, but needed to make a small adaptor to measure the end float on the crankshaft before I do so. This particular engine has a little bit of movement in the rear crank pin, and I need to find out why it has moved.

The early M6 back plate is on the left and the later M8 is on the right.



The holes are bigger on the later one, which means more oil can be supplied to the rear bearing. After measuring these it equates to an improvement of 15% over the earlier design.



Brian’s engine will be increased further still, to match the front crankcase drilling. In the meantime I am waiting for another plate as Brians is damaged around the rear seal area, and it looks like something, a fastener possibly, has got between the flywheel and the rear plate!