i own a 03 660 with extensive ingine work, 686, 12:1 piston, drag cam, +1 valves, port and polish. all this work done by duncan racing. but i dont think my bike is running at its full potential, it has good bottem and mid power, but it falls on its face on the top. relativley stock machines that i could beat when my machine was stock, are now staying with my machine. im thinking it has to do with my stock carbs, and stock ignition. i was thinking carbs can't keep up with the fast reving cams. if carbs the problem anyone have an idea's on carbs. also anyone use the grizzly 2-1 intake on there rappy; i would like to have single carb set up.

 

If you're running out of top end power now you'll be a lot worse off with a single carb.

Either go with EFI - 1400 bucks
Or Keihin FCR dual carbs (39mm) - 900 bucks or so