1980 cb750k engine revs up....

[Benshea]

I bought this bike about a month ago, when i first got it it was ok, but after a few weeks one night after working on the bike, cleaning it. after the bike got warmed up, if it was sitting it would idle good, but when I pulled the throttle back it will stay reved up, if I put it in first gear and let the clutch go and almost let it stall the rpms will go back down most of the time, sometimes it will go back down and then come up gradually. it also does it in neutral. when I stop at a stop sign.
I checked the routing of the cables and they are good, put some lubricant on the cables, set the idle screw a few times.
i'm going to change the intake manifold boots, so we'll see what happens, but I just wanted to see if you guys have any ideas.

Thanks

 

[my-79-750-k]

Sounds like an air leak somewhere, that or the spring on your idle adjustment screw is jacked and won't hold tension on it. Money is on air leak though.