Colin .... as a temporary measure have you thought of trying a supplementary baffle .... easily available and cheap as chips .... I carry one in case my racer falls foul of the noise scrutineers and I need to quieten it before competing .... I've found they have very little effect on performance even on an engine that revs to 14,000. .... might give your ears some relief while you're sorting a more permanent solution.

Like this


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K