Has anyone had troubles with surging/stuttering between 4-5000 RPM? This bike is a california model (residing in Colo.)and since day one, it has had an aweful dead spot at 4200 rpm. It seems that the lower the gear that you are in, the worse the symptom. In 3rd or 4th gear at 4-5000 rpm, It is difficult to hold a steady rpm/speed.