Honda CB650

The Honda CB650 is a four-cylinder middleweight motorcycle manufactured from 1979 to 1985 by Honda. The machine was largely based on the Honda CB550 and the 1979 model had the same frame and speedometer as the Honda CB550 of the 1970s. The tachometer had different gearing and is not interchangeable without also replacing the cam and tachometer drive gear. The 1979-1982 CB650's engine had the same engine block as the CB550, but was bored out to 626 cc. The SOHC four-cylinder, eight-valve engine had added domed pistons and produced 63 hp (47 kW) @ 9,000 rpm.^[1] The CB650's performance was comparable to contemporary DOHC 750 cc motorcycles because of it being built on the lighter, more compact chassis of the CB550. It was Honda's last SOHC air-cooled straight-four engine, which was a culmination of the engine technology of Honda up to that time.

Model history

The CB650 was introduced in 1979.

In 1980, the newly re-styled CB650 used the same 626 cc engine as the previous year. The 1981 and 1982 models again used the same engine, but with a different head and vacuum carburetors instead of the mechanical carburetors used in 1979 and 1980. It was now available in either Standard or Custom configurations. The style changes focused on a new teardrop tank, chromed air-box, and smaller side covers. The 1980-1982 Standard model featured 4-2 exhaust pipes, a black plastic headlight bucket, and wire-spoke wheels. The Custom model featured 4-4 exhaust, Comstar wheels, a chrome headlight bucket, and in 1981, dual disk front brakes and air assist forks.

The second generation was produced from 1982 to 1985. In 1982 the Nighthawk replaced the Custom of the previous years and featured a re-designed tank and side covers, however the standard model of 1982 remained much like the previous year's model. In 1983 a new Dual Overhead Cam (DOHC) engine replaced the Single Overhead Cam (SOHC) engine used since 1979. The DOHC engine had hydraulic valve lash adjusters and was rubber mounted; and final drive changed from chain-drive to shaft-drive.

References

1. [Cycle Guide Vol.13, No.12 December 1979].