nunrleft
CB750 Member
I just bought an '81 CB750. It's in good condition with a sidecar attached. It was one of those "Ran When Parked" deals. 46,xxx miles on the bike. Price was extremely good. Seller said the carbs were rebuilt professionally over the winter by someone in California who also synched them to their engine before sending them back. Seller said the battery needed to be replaced, gas added and should run fine. Seller also stated the #3 cylinder was a little low on compression and it most likely needs a valve job.
I'm not new to bikes and currently own an '87 Honda Super Magna, '82 Kawasaki KZ440 and a '73 Yamaha DT3 which I restored. I put a new battery in the CB, added gas and of course all the carbs leaked out of the over flows. Tapped on them with a pipe and the floats released and they stopped leaking. Went to fire it up and found that the starter didn't want to engaged. Quickly found a bad switch at the clutch lever.
Got her to fire up and the center two cylinder head pipes are cold. Won't rev past 4,000 and obviously only running on two cylinders. I'm pretty good at diagnosing problem and will of course check spark, compression, etc. However, I'm new to the DOHC CB750. Is there anything known issues or things that commonly happen which would cause the two middle cylinders to fail?
I'm not new to bikes and currently own an '87 Honda Super Magna, '82 Kawasaki KZ440 and a '73 Yamaha DT3 which I restored. I put a new battery in the CB, added gas and of course all the carbs leaked out of the over flows. Tapped on them with a pipe and the floats released and they stopped leaking. Went to fire it up and found that the starter didn't want to engaged. Quickly found a bad switch at the clutch lever.
Got her to fire up and the center two cylinder head pipes are cold. Won't rev past 4,000 and obviously only running on two cylinders. I'm pretty good at diagnosing problem and will of course check spark, compression, etc. However, I'm new to the DOHC CB750. Is there anything known issues or things that commonly happen which would cause the two middle cylinders to fail?