Topic: Carbs don't snap back even without cables connected

[evanphi]

Manually operating the butterfly with no cables attached. Open to full throttle, let go, carbs snap to 2/3 closed, and slowly drop the last 1/3 of slide travel. Again... no cables attached.

Are there bushings on the lifters that need oiling? Lube the slides? New spring? I just pulled the carbs and cleaned the jets, but didn't have the slides out or anything.

Was snapping closed just fine before I had the carbs off,as far as I can remember.

1975 CB750K.

[Johnie]

Try loosening the the carb slide tops to reseat the slides. They maybe are hanging up in there. If you never had the slides out then they may need a cleaning.

[evanphi]

Try loosening the the carb slide tops to reseat the slides. They maybe are hanging up in there. If you never had the slides out then they may need a cleaning.

They were snapping back fine when I had them off the bike.

By slide tops you mean the screw on caps that go on each carb body?

[flybox1]

A few ideas...
Return Spring is not doing it's job. Too weak, not original, or not connected.
Slides are varnished.
Bent needle or varnished needle jets.

[Johnie]

Yes, the screw caps. It was just an idea as I had the slides out and tightened those caps down to soon. They were a little out of line with the slide shaft.

[Sprocket75]

Loosen the screws on the plate that all of the carb bodies are attached to. Then loosen the linkage a little between them. Start snugging them back down little by little checking the slide action as you go. Tighten where necessary. Sounds like you've got them torqued/torsioned somehow. I had the same exact issue when I took mine off. This solved it for me.

[evanphi]

Thanks for the suggestions so far. Won't be back out to the bike for a few days, but I will pull them off again and check them over.

[jtb]

Loosen the screws on the plate that all of the carb bodies are attached to. Then loosen the linkage a little between them. Start snugging them back down little by little checking the slide action as you go. Tighten where necessary. Sounds like you've got them torqued/torsioned somehow. I had the same exact issue when I took mine off. This solved it for me.

+1