| MODEL | VELOCETTE VIPER SCRAMBLER 1958 - 1968 |
| Year | 1958 - 1968 |
| Engine Type | Four stroke, single cylinder |
| Displacement / Capacity | 349 cc / 21.3 cu in |
| Bore X Stroke | 72 x 86 mm |
| Compression Ratio | 9.3:1 |
| Cooling System | Air cooled |
| Max Power | 26 kW / 29 hp @ 7000 rpm |
| Max Torque | — |
| Ignition | BTH racing magneto |
| Induction | Amal TT monobloc |
| Start System | Kick start |
| TRANSMISSION SPECS | |
| Lubrication | Dry sump |
| Gear Box | 4 Speed constant mesh, close ratio |
| Clutch | Dry, three-plate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Telescopic fork with hydraulic compression and rebound damping |
| Rear Suspension | Woodhead-Monroe springs with hydraulic damping, later Armstrong and Girling, adjustable |
| Front Brakes | 7 x 1 in drum |
| Rear Brakes | 7 x 1 in drum |
| DIMENSION SPECS | |
| Overall Length | 2260 mm / 89.0 in |
| Overall Width | 890 mm / 34.5 in |
| Overall Height | 1090 mm / 43.0 in |
| Seat Height | 838 mm / 33 in |
| Wheelbase | 1365 mm / 53.75 in |
| Ground Clearance | 165 mm / 6.5 in |
| Dry Weight | — |
| Wet Weight | 152 kg / 330 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.00 x 21 in |
| Rear Tyre | 4.00 x 19 in |
| FUEL SYSTEM | |
| Fuel Capacity | 11 Litres / 3 US gal |
| Fuel Consumption | — |
| Top Speed | — |
An off-road version of the 350 Viper, built by the factory development team in a small batch from December 1958. It was set up for rough going with a 21 in front wheel, wide-ratio gearing, a megaphone silencer, a small tank and a higher state of tune than the road bike.
