----- Original Message ----- From: Helg Bredow <[EMAIL PROTECTED]> > I've got an old CB750 that runs well at anything up to 80kmph but > anything over and the engine starts missing on one or more cylinders. > > I've just adjusted the needle position in an attempt to rectify it and > the spark plugs are now a nice tan colour, instead of black
What you don't say is what size main jets you have and also whether this problem suddenly appeared or whether it's done it since you got the bike. Is it missing on all four? Does it make any difference whether the motor is under load or not? Several things spring to mind - first set tappets, points and timing and fit new spark plugs. Remove float bowls and clean the jets (always assuming you don't find a jet in the bottom of the float bowl). Do you have a standard air filter. If anyone has had the carbs in bits - uh oh stupid me, you must have to alter the needle position, so you should put them back to the centre - check that the slide cutaway faces the air filter side, NOT the engine side. All done? Did it help? and the only cost incurred is the plugs. Paul H
