The Honda CX series motorcycles, including the GL500 and GL650 Silver Wing variants, were developed and released by Honda in the late 1970s, with production ending in most markets by the mid 1980s. The design included innovative features and technologies that were uncommon or unused at the time such as liquid cooling, electric-only starting, low-maintenance shaft drive, modular wheels, and dual CV-type carburetors that were tuned for reduced emissions. The electronic ignition system was separate from the rest of the electrical system, but the motorcycle could only be started via the start button.
Power train
Engine
The CX series features a crankshaft configuration [aligned transversely] across the frame of the bike, similar to the Moto Guzzi layout. Unlike a "boxer" flat-twin, the cylinders protrude at an angle above the horizontal. The included angle of the CX is 80°, and the heads are twisted 22° so that the inlet tracts do not interfere with the rider's legs. A camshaft nestles at the base of the V between the cylinders. Although Honda generally favors OHC engines, the cylinder head twist necessitated the use of stubby pushrods to operate the four overhead valves per cylinder, with a forked rocker arm acting off each pushrod. The 5-speed transmission is located below the crankshaft, with both in the same housing, an arrangement which keeps the engine short (length wise) but quite tall. The engine has a 10.0:1 compression ratio and 9,650 rpm redline. Just as with the Honda Gold Wing, the transmission rotates opposite to the engine to help counteract the engine torque's tendency to tip the bike slightly to one side when the throttle is opened or closed.
The CX was the first V-twin motorcycle that Honda ever built. It was initially designed as a 90 ° V-twin. Honda built a prototype CX350 but it was never released to the public. In that version the cylinder heads did not have the cylinder-head twist.
Transmission
Final drive is with a shaft. Power is transferred by an enclosed splined driveshaft with one universal joint. The shaft drives a bevel gear to which the wheel is joined via a cush-drive, which absorbs and dampens driveline shocks and vibrations. The bevel drive spins in an oil bath, and a grease-nipple is provided for greasing the shaft bearing.
Wheels
The ComStar wheels combine the flexibility of spoked wheels with the strength and tubeless characteristics of one-piece wheels. Honda introduced the Com-Star wheels a year or so earlier on the CB250T/400T Dream as well as on the CB750F2 and GL1000 Gold Wing, although these featured standard rims that required inner tubes. The CX500 was the first production motorcycle to use tubeless tires.
Chassis
Early versions had conventional suspension, consisting of hydraulically damped telescoping front forks and dual coil-over shocks at the rear. Later versions had air-assisted forks and featured Honda's Pro-Link monoshock rear suspension. US bikes (except GL500I, GL650I and Turbo) were equipped with a single front disc brake whereas all other bike possess dual front disc brakes. Besides the 'vanilla' CX500B, models after 1980 sport dual piston calipers replacing the single piston caliper of the earlier models. For the Turbo and Eurosport models the rear drum was replaced with a dual piston caliper and disc. All models feature steel tube frames with a large backbone, with the engine used as a stressed member. The dual shock models use a single tube backbone whereas the later Pro-Link models employed a triple tube backbone.
Variants
CX500
The 1978 CX500 Standard had a large fuel tank, stepped seat, a round brake fluid reservoir and a plastic mini-fairing that was thought to look unusual at the time. Turn signals extend out through the mini fairing from the headlight's centerline. The CX500 Standard had silver Comstar wheels, 19 inch in front and 18 inch in the rear.
While V-twins were nothing new, as Moto Guzzi had been mounting them with the crankshaft inline with the frame with shaft drive for many years, this Honda was decidedly different. Not only was the 497 cc engine water-cooled, but it had four valves per cylinder that were operated by pushrods rather than the overhead cams favored by Honda on its previous four-stroke engine designs.
The styling was radical and upright forks and a short engine contributed to a stubby wheelbase on a bike that was rather tall. The CX500 was one of the first recipients of Honda's new Comstar wheels (and later, on B models, reverse Comstar and a square brake fluid reservoir), which measured in front and at the back.