The Velocette Viper was a 349 cc single-cylinder motorcycle made between 1955 and 1968. Built with traditional methods and materials, it struggled against more modern machines, so from 1960 the designers added glass fibre enclosure panels and a Clubman racing version.
Velocette Viper at a glance
| Maker | Veloce Ltd, Birmingham |
|---|---|
| Production | 1955–1968 |
| Engine | 349 cc single-cylinder four-stroke |
| Developed from | Velocette MSS 500 |
| Introduced | October 1955 |
| Bottom end | shared with the Velocette Venom |
| Finishes | black or willow green |
| Enclosure panels | glass fibre, from 1962 |
| Clubman version | from 1960 |
| Scrambler | 25 built in December 1958 |
| Viper Special | November 1962 |
Based on one source: the English Wikipedia article on the Viper.
History of the Velocette Viper
A 350 from the 500
The Viper was introduced in October 1955. The single-cylinder machine was developed from the 500 cc Velocette MSS, which also produced the almost identical 500 cc Venom, and it used the same bottom end as the Venom. Designed by Charles Udall, its 349 cc engine had a bi-metal cylinder with a cast-iron liner, a high-compression piston and a light alloy cylinder head. The Viper carried plenty of chrome plating and was offered in black or willow green.
Glass fibre enclosure
From 1962 the Viper was one of the first production motorcycles to be fitted with glass fibre enclosure panels. The panels reached from the front of the engine, level with the top of the crankcases, back to the rear pillion footrests, and were made by Avon for Velocette. They were practical, keeping oil off the rider’s clothes, but proved unpopular with traditional buyers of Velocette singles.
The Clubman
From 1960 Velocette also produced the Viper in a Clubman racing version with Amal TT carburettors, a BTH racing magneto and a close-ratio gearbox, and the compression ratio raised to 9.3 to 1. The Clubman did without the glass fibre enclosure and instead showed off highly polished crankcase and gearbox castings. It came with rearset controls, lowered handlebars and a steering damper, and could be ordered with a megaphone silencer, a rev counter and light alloy wheel rims.
Scrambler and Special
In December 1958 the Velocette development team built 25 off-road Vipers and sent them to the United States for evaluation in enduro events. Built to Clubman standard, the Scrambler had a specially lightened frame and a high-level enduro exhaust. The Viper Special followed in November 1962 with a three-gallon tank, a pressed-steel full-width front hub, the MSS rear hub and a 100 mph speedometer in a modified headlamp nacelle.
Design and features
- Velocette single: a 349 cc engine with a bi-metal cylinder and light alloy head.
- Venom bottom end: the crankcases and lower engine were shared with the 500 cc Venom.
- Enclosure panels: quick-detachable glass fibre bodywork from 1962, made by Avon.
- Clubman specification: racing carburettors, magneto and close-ratio gearbox from 1960.
- Viper Special: a larger tank, full-width hub and 100 mph speedometer from 1962.
Velocette Viper versions
- Viper (1955–1968): the standard road single, later with glass fibre panels.
- Viper Clubman (from 1960): Amal TT carburettors, BTH magneto, 9.3 to 1 compression.
- Viper Scrambler (1958): 25 machines for American enduro evaluation.
- Viper Special (1962): three-gallon tank, full-width hub, 100 mph speedometer.
The Viper’s 500 cc sister was the Venom, and both grew from the MSS. More machines are in the Velocette collection.
Sources
- Velocette Viper, English Wikipedia: development, Clubman, Scrambler, Special
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