No, it's not piston ported...so you wouldn't gain any performance there. (except for marginally lightening the piston )</p>

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The ST .90 is more of a torquer, not really a revver...but some "softening" of the sharp edges in the mixture's flow path might prove beneficial?
You might find a burr or something along the edge(s ) of the ports that caused the scratches, so dis-assembly might be worth while.</p>

Once broken-in and the carb is adjusted properly, they are (or can be ) nice running engines.

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