I bought a VN750 '06 a couple of months ago. It is new, and has about 900 miles on it. I've started using higher throttle settings now, since it's through its initial break-in. I've noticed that at about 3/4 throttle, or higher, the engine misfires a lot, and power isn't as good as I would expect. The engine and fuel system are still stock. I live in Utah, and the bike operates at an elevation of about 4500'. Could the misfires be caused by a less then optimal main jet size?

Thanks.

The misfires could be caused by an improperly seated vacuum hose in the right ear. (air filter) make sure it is not pushed in too far and the tip is cut at a 45 degree angle. This prevents it from "bottoming out" and causing high rpm stumbling due to incorrect air flow