I do exacly that to all my 2 strokes. it`s a great way to wake up an engine.thats why I get 13300 rpm on the 12.25 prop on my asp xls 52. Normally this engine and prop will give 12800 rpm. I have also done this on my os 91 fx, but did not tach it before modifying it so I don`t now how many rpm`s I gained, but the engines power in flight was greatly improved. go ahead and do it kostas