Background o

Liquid-cooled V-twin engines ranging from 125 cc to 1800 cc displacements power a variety of Honda Shadow motorcycles. The Shadow shares many of the Honda CX series mechanical components and Honda designed it to compete in the cruiser market in the United States. Honda produced the VT750c for the domestic market, but had to manufacture a 699 cc version of the 750 cc in 1983 to avoid U.S. tariff restrictions on bikes equipped with engines displaced by more than 701 cc. Honda abandoned the 699 cc version for the 750 when the U.S. government lifted the tariff in 1985.

750 Engine Origins :

o The Shadow 750 cc engine's lineage dates to the 1970 Honda 750. However, the version that served as the contemporary Shadow 750's template was the 1975 Honda CX series cruiser equipped with the CB750F and CB750F2 V-twin engines. The CB750F was an early liquid-cooled shaft-driven version with a four-into-one exhaust system. A year later, Honda introduced the CB750A with the motorcycle maker's first automatic transmission. In 1979, Honda developed the CBX Super Sport CB750F equipped with a double overhead cam and 16 valves. A V-Four version of the 750 arrived in 1982 with the Honda Magna VF650S Sabre and VF750C Magna.

Original Specs:

The 1983 Honda Shadow VT 750 C model was a custom-cruiser. The liquid-cooled engine actually displaced 749.5 cc, or 45.75 cubic inches. It was a V-twin four-stroke model with a 9.8-to-1 compression ratio. Its bore was 3.1 inches and the stroke was 3 inches, which never changed during its production run. A dual carburetor system delivered the fuel and the ignition was electronic. A six-speed transmission shaft-drive transmission with a Sprague one-way clutch transmitted the power to the wheels.

Trendsetter o

The Honda Shadow was a revolutionary bike. Honda designed the engine to achieve primary balance with a dual-pin crankshaft and the Sprague clutch that featured a modest one-way slip to reduce wheel chatter during high rpm downshifting. It was the first engine in which Honda used three valves.

It gained a reputation for low maintenance due to improvements over previous 750 cc engines with cam chain tensioners, brushless generator, electronic ignition, hydraulic valve adjusters and the shaft-drive transmission.

Little had changed in the Honda Shadow 750 by 2011. Honda trimmed the actual displacement of the 2011 Honda Shadow Spirit 750 to 745 cc, but the engine remained a V-twin four-stroke. The motorcycle maker dropped the compression ratio slightly to 9.6-to-1 and replaced the original dual carbs with a single 34 mm constant-velocity carburetor for better efficiency.

The Shadow Spirit model had a five-speed shaft-drive transmission.