As the throttle by cable bikes getting old, we have seen this problem more often. High idle and throttle position jumping at idle are telltale sign of broken shaft inside the throttle body. Unfortunately, 01-05 stock throttle body has been discontinued and can’t get from the factory. However, @horsepowerinc offers OEM direct replacement -HPI-45D1-R- that bolt right on to OEM manifold. Not a performance upgrade but better throttle shaft construction and not involving re-tuning bikes after install