RidingSince1969
CB750 Member
I recently got my CB750K3 on the road -- the bike was given to me last summer, and I've spent the last year fixing it up.
I'm happy with the way it runs -- except for one thing. It's highly responsive at low throttle openings, but when above half throttle or so (main jet?), the engine bogs down. If you just leave the throttle open, the rpms will "catch up." I just had it out on the highway, and it will run 70+ mph and stay there -- but it takes a while to get there. It feels like it's not getting enough gas, but it eventually gets what it needs.
I eliminated the possibility of restricted air intake by removing the air filter and bottom of the air box. No change. The carbs originally were gummed shut from sitting for 15 years, so over the winter I cleaned them, including carefully reaming all the jets. I've also installed new plugs, changed the oil, and set the timing.
Any ideas. I'm under the impression that it's something simple, since the bike runs great otherwise . . .
I'm happy with the way it runs -- except for one thing. It's highly responsive at low throttle openings, but when above half throttle or so (main jet?), the engine bogs down. If you just leave the throttle open, the rpms will "catch up." I just had it out on the highway, and it will run 70+ mph and stay there -- but it takes a while to get there. It feels like it's not getting enough gas, but it eventually gets what it needs.
I eliminated the possibility of restricted air intake by removing the air filter and bottom of the air box. No change. The carbs originally were gummed shut from sitting for 15 years, so over the winter I cleaned them, including carefully reaming all the jets. I've also installed new plugs, changed the oil, and set the timing.
Any ideas. I'm under the impression that it's something simple, since the bike runs great otherwise . . .