Domi-Racer

It is a fact that Mahle in Germany made racing pistons for 500cc Norton Dominators before. But they had a compression ratio higher than 10:1. Contacting them to see if they still have the information they used to make them is on my list of things to do.....

Red Lizard Motorcycles on the Isle of Man sells Dominator pistons that are supposed to give about 9.5:1 with the SS head. I think they are new Hepolites made either in Australia or somewhere else in the far east for about 270 English pounds per pair.

Venolia in the USA used to make forged racing pistons for the Dominator also. So if you need a really strong forged alloy piston for serious racing you are probably going to have it custom made by a piston shop.

The 1964 Norton 88 racing bikes prepared by Paul Dunstall used standard 88ss pistons, the tops of the cylinders were machined down .033" to give 10.4:1 compression. At that the engines put out about 52bhp. These bikes were run in the 200 and 100 mile races at Daytona that year and did very well, getting a 1st and 3rd in the 100 mile race and a 7th and 8th in the 200 miler. So standard cast pistons have been really useful in racing Dominator Nortons in the past....