Smaller rear sprocket=More speed.

You can also open up your exhaust (cut or remove the baffle) clean up the intake and exhaust ports, install a thinner base gasket and a lot of other things for a little more power.

More power=less reliability, though when done right, I think you could get a modest power boost without too much sacrifice.

Also remember when making "adjustments" to a two stroke bicycle motor, to keep an eye on the jetting so you don't fry the engine.

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If it ain't broke, and you mess with it long enough, it will be.