lol thanks Andy, I will say Shell Optimax is not the way to go with lightly tuned engines, "tests have shown up to a 2bhp loss compaired to standard unleaded". Anyone with knowlege of calorific values will understand why Optimax will lose power on this type of engine.

Stick to a normal unleaded or super unleaded. If your bike doesn't pink or knock on unleaded there is no point going super. All you are doing is buying fuel which effectivley burns slower and will produces less power. If you do suffer from pinking then yes you need a fuel with a higher C.V. or RON rating. Most of our bikes here, even the race ones, will be fine on bog stock unleaded.

Like blinka says tho, if you're running a little more advance, that sometimes can push the detination point of fuel a little too close, so a higher spec fuel is needed. But you can often get away with at least 2deg advance and raising the C.R a ratio before it's needed.
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If I have to take the carbs off once more...