CB750C Custom Hard Time Accelerating

[nwool05]

I have a 1982 DOHC CB750C Custom that recently started having a hard time accelerating in the power band (6-9 RPM), and in 5th gear, won't exceed 5,500 RPM with wide open throttle. I took off the carbs and cleaned them and replaced my spark plugs since the plugs were fouled from running rich.

After doing all of it, I took it out on a ride and tried it again, and it didn't fix anything. My next thought is to see if my fuel valve is gunked up and then clean it, and also tune my carburetor though it didn't need it before. Is there any other things I should look at/examine as to what could be causing this issue?

 

[blingbao]

Definitely sync the carbs

 

[nwool05]

Definitely sync the carbs

Problem was fuel delivery from tank to carburetors, I got it fixed.

 

[Stan C]

I have a 1982 DOHC CB750C Custom that recently started having a hard time accelerating in the power band (6-9 RPM), and in 5th gear, won't exceed 5,500 RPM with wide open throttle. I took off the carbs and cleaned them and replaced my spark plugs since the plugs were fouled from running rich.

After doing all of it, I took it out on a ride and tried it again, and it didn't fix anything. My next thought is to see if my fuel valve is gunked up and then clean it, and also tune my carburetor though it didn't need it before. Is there any other things I should look at/examine as to what could be causing this issue?

Ignition wires ! I had the same issue. Bike starts spitting and misfiring around 7500 RPM. It suddenly came to mind to check the wires and they seemed like the original ones because all the fittings were loose fitting. I purchased some new automotive ignition wires from CTC and made up new ones to fit. I also installed a new set of plugs not knowing the age of the old ones. Low and behold----9500 RPM without one spit or complaint.