My CB900 sat in storage for about five years. The fuel did have stabilizer in it though. I dumped the tank and refilled with ultra-hi test and put in a new battery. It started within seconds but once it gets going it revs to about 6500 RPM's steady and won't back down. The throttle moves and will allow higher rev and the choke cable moves as normal. Any ideas about what is going on in the fuel sytem?