Motorcycle Repair: bike revs to high in neutral, honda cb 450, throttle grip

Question
i have a 1983 honda cb 450 nighthawk and it runs ok just a small problem is that in neutral it revs a 4300 and i dont think that is right so what could be the problem and how can i fixs it

Answer
It is most likely that the idle speed adjustment is out of whack. To adjust it, follow the throttle cable all the way from the throttle grip at the handlebar to where it attaches to the carbs. Take a close look at the linkage it attaches to and you will see that there is a small spring loaded screw or thumbwheel that the linkage rests on when the throttle is closed. With the bike running and the motor warmed up, slowly turn the screw in a counter-clockwise direction until the idle speed slows down to around 1,000rpm.

Note that you might need to get the carbs cleaned and synchronised if adjusting the idle speed doesn't make the motor run any better.