History of the Nighthawk...
Honda introduced the Nighthawk in the 1982 model year. It was initially produced in three sizes, the CB450SC, CB650SC & CB750SC models. All of these models borrowed heavily from the existing CB models, yet there were enough styling and substantive improvements to warrant designating them as new models. The CB450SC Nighthawk was an improvement upon the CB400, with an increase in engine size, improved internal lubrication system, hardened transmission gears, six speed tranmission, chain drive, cast wheels, disc front brake, air-adjustable fork, and VHD shocks. In its first year, the 650 Nighthawk was equipped with Honda's last remaining SOHC in-line 4 cylinder engine, a 5 speed transmission, chain drive, and Comstar wheels. The CB750SC Nighthawk began its run as a chain drive, 16 valve, DOHC in-line four cylinder, using the existing CB750 engine, but with everything else restyled and redesigned.
1983 brought many changes. The CB550SC Nighthawk, a cruiser styled Nighthawk, was introduced. The CB650SC Nighthawk was totally redesigned, producing a package which rivaled other companies 750's, including shaft drive, self adjusting cam chains, improved braking, handling, ergonomics, and visual appeal. The CB750SC was still offered, but not for long! In 1983 the U.S. government, in an effort to keep Harley-Davidson afloat, imposed strict tariffs on imported motorcycles exceeding 700cc's. The 750 Nighthawk S was produced in 1984-86, but it wasn't sold in the USA. If you get ahold of one, chances are it is from Canada. The 450 model remained unchanged.
In 1984, the largest U.S. Nighthawk, the CB700SC, was introduced. It hit the showrooms with an all new engine, with DOHC and automatic cam chain tensioners. The bikes were shaft driven, and came standard with a small fairing, giving the bike a sportier appearance. This model remained until 1986, the last year of the Nighthawk's initial existence. The 550 was dropped after the 1983 model year, except in Canada where the CB550SC-E was produced. (I don't believe this Canadian version was produced any time after 1984.) The 650 saw its last production in the 1985 model year.1987 brought sportier bikes, cruisers, and touring rigs, but no Nighthawks!! This intolerable situation persisted until 1990, when Honda, finally realizing the error of its ways, resurrected the Nighthawk series in the 1991 model year. The standard bike was reborn!! The new version came in two sizes, a 250cc twin, and a 750cc inline 4 cylinder (size was not a problem now that Harley-Davidson
was healthy again). Both of these machines were very well designed and affordable, a package hard to beat. Having achieved perfection at last, Honda has wisely left the design untouched , except for moving the location of the helmet lock in the 93 and later bikes, color changes, and a blacked out engine in 1997 and later bikes).