For cost-saving purposes, the CB650 was designed to be produced on the same production line as its CB550 predecessor, using the existing tooling.

After 1981, the CB650 had a modified cylinder head and new CV vacuum carburettors, and the bike was now available in either Standard or custom configurations.

The 1980–1982 Standard model featured 4-into-2 exhaust pipes, a black plastic headlight nacelle, and wire-spoked wheels.

The custom model featured 4-into-4 exhaust, Comstar wheels, a chrome headlight nacelle, and in 1981, dual disc front brakes and air-assisted forks.

In 1982, replacing the Custom, the new Nighthawk featured a re-designed tank and side covers, while the 1982 Standard model remained largely unchanged.