Will Loder Wrote:from my experience the 750 and 850 weslake engines are a lot more reliable than the 500, presumable because most of the same parts are used but the engine isn't rev'd nearly as hard.

I'll bow to your exprience Will, and wish Dave all the best with it. Lovely bloke and has helped me out lots. My own experience FWIW comes from racing 750, 830 and 920 Nortons back in the 70s and 80s. Reliability was OK on the smaller engines but I used to get through 2 sets of cases a year with the 920, they just couldn't take the extra grunt from the engine.