rcuttler
CB750 Member
I've got a '77 CB750K with 25,000 or so miles on it. I always had problems with the bike starting on only two cylinders but the other two would come in after some warming up. Recently I decide to do something about and pulled the carbs, cleaned them up, replaced some gaskets\o-rings. I also replaced all the air tubes connecting carbs to the motor and air box to carbs, as well as changed out a clapped out air box for a solid one, with good recent use filter. Bike now starts up like a champ on all cylinders. But now I've got a new problem. Once it warms up the idle speed won't come down below some 2,800 rpm. The cables had been lubed in the last year, but I don't see how it can be a cable problem anyhow. The throttle turns freely closed with no drag. The idle speed adjuster is now out of play as I turned the screw out sufficiently that it no longer comes near to touching its seat. I've sprayed around the whole area with ether, getting no reaction at all. The pull cable pulls (throttle up) and the push cable pushes (throttle down). The only thing left I can think of it the problem is in the bell crank the cables connect to, but I can't imagine how that would work, as the first couple of minutes of riding everything is fine. The problem starts as the bike warms up. Any ideas?
Bob
Bob