Engine cutting off when trying to accelerate

[nateweisiger02]

Hey there, I have a 78 cb750f. It has been sitting in a barn about 10-15 years. After un-seizing the engine, a bit of electrical work, cleaning the carb 3 times, and a battery, got it fired up and driving again! I have driven it around my apartment complex for about 20 minutes, didn’t run great but it did run and I could drive it around. Would like to add I do not have the air box back on it yet. But went to drive it yesterday and it would Idle in neutral just fine, and I could rev the engine and it would do fine, but as soon as I put it in 1st and start letting off of the clutch, the engine bogs down and cuts off unless I pull the clutch back in or put it in neutral. Any idea what could be happening or going wrong?

 

[madmtnmotors]

My money is on carbs. I just finished two sets of 78' CB750 PD carbs this weekend. One set was leaking and the other set had been badly repaired with some serious neglect on top of that. These later carbs require some intestinal fortitude to rebuild successfully.

Have you checked the condition of the spark plugs and timing? I would start with the 3000 mile tune up and go from there. A compression check might be a good idea too.

 

[dirtdigger]

I also would say start going through all the basic tune up stuff. Compression, valve adjust, timing chain adjust, point condition???....clean or replace, set timing.dwell. Sync carbs. New plugs. Condition of plug wires and caps? Spark at all 4 plugs? It sounds like it isnt running terribly well so need to start with all the basics and see if it still dies when you are starting out.

 

[nateweisiger02]

Okay good deal, I will do a rundown of the things that y'all listed then reply back in the chat.