CB650

The Honda CB650 is a 627 cc standard motorcycle manufactured from 1979 to 1985. It was given a 4-cylinder air-cooled SOHC wet-sump engine, with two valves per cylinder. The CB650 was based on the CB550, which itself was derived from the earlier CB500. The CB650 was the last of Honda's successful series of air-cooled SOHC fours that began in 1969 with the Honda CB750. However, If your CB650 need some tuning up, having a Honda CB650 service manual can prove to be helpful.

To save money, the CB650 was designed with the intention of it to be manufactured on the same production line as its CB550 predecessor. The CB650's cylinder block was new in design, but it had the same stud holes of its predecessors. Likewise, the frame was nearly identical to that of the CB550. Handlebar levers and instruments were also shared betwix the models. 

The CB650 was re-styled in 1980, but there were no significant mechanical changes. After 1981, the CB650's new CV vacuum carburetors and cylinder head were modified, and the bike was made available in either Standard or custom configurations. The 1980–1982 Standard model featured 4-into-2 exhaust pipes, wire-spoked wheels, and a black plastic headlight nacelle. 

A second-generation model was manufactured from 1982 to 1985. Replacing the Custom in 1982, the new Nighthawk was given a re-designed tank and side covers, while the 1982 Standard model remained mostly unchanged. In 1983, the SOHC engine was replaced by a new rubber-mounted DOHC engine featuring hydraulic valve-lash adjusters; and final drive was changed from chain to shaft-drive. So, if you ever need to tune your CB650, check out a Honda CB650 repair manual to make sure you do it right the first time around.