Engine cases

For as long as I can remember, there have been rumours circulating that the 749RS crankcases may have been painted sand cast rather than the standard road cases.

Sand cast cases are stronger than road cases and can withstand higher revs for longer intervals than road cases.

This weekend, I had cause to look at the cases I bought with the bike. These cases are both factory (see the F0 designation), from '04 and '05. They are both standard road cases - not sand cast. It seems that the teams were happy to run the standard road cases on the early bikes, although they may have switched to sand cast later to reduce maintenance and associated costs. 

This means that any 749Rs that have been fitted with the engine kit (heads and cams) have essentially the same motor as the Breil race bikes. There are a few differences, but essentially, the motor - cams, heads, valves, pistons, rods, cranks and cases - is the same.