Harold wrote:Has anybody used the 275cc big bore kit from Firefox racing UK?The advertisement is not that clear,the barrels shown looks like new 150 SP but states that MC21 tops are internally cut to accept the bigger bore.

I mailed them about this kit, ignore the pics they are "just" boring out NSR barrels and fitting bigger pistons.

I remember talking to Andy about it and he reckoned back when Eric Gorr was doing this sort of thing that he reckoned you could go out that far as it cut into the RC valve too much.

The good thing about the 300 kit is it's brand new barrels. They alone are worth 80% of the cost of the kit.
Other than that for what you're spending on either this 275 or 300 motor you could get a better 250 motor built.
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