Machining Services and Special Products

Timing Disc Adapter

Locating a timing disc on the crankshaft has long been a hit and miss affair. We have developed a threaded boss to fit the end of the crank with a 1” dia section to locate a standard disc. The disc is retained by a threaded collar. The arrangement is intended for static timing of valves and ignition.

Twin Spark Squish Head. (Venom Stage 1)

The standard M17/8 cam fitted to most Vipers and Venoms is optimised for maximum power. Im doing so it loses low end torque and a degree of flexibility. The single plug, hemi-head is typical of its day but is inefficient by modern standards, requiring 38 deg ignition advance, which wastes fuel and power. The high crown piston results in an inefficient flame path. Velos, of course, made the MSS but this was a much milder engine ideally suited to sidecar use.

To address these issues we have developed a twin spark, squish band head conversion, based on a standard Viper head, a revised cam profile, and a MSS type, flatter top piston, which reduces the ignition advance to the 30 degree zone. The second spark plug, positioned on the opposite side of the combustion chamber, equalises and reduces the flame path, whilst the squish band promotes improved turbulence and mixing of the charge. The exhaust stub is increased to take a Venom sized pipe.

This results in a more tractable, flexible engine, which is more relaxing to ride, without sacrificing much in the way of outright power. The compression ration is 8.5, similar to a standard Venom. 

The benefits are:-

  • Easy starting

  • Steady tick-over at about 700rpm

  • Increased Torque available from 1500rpm

  • Improved spread of torque over the full rev range.

  • Less gear changing 

  • Improved fuel economy in all circumstances (especially if a 19 tooth gearbox sprocket is used)

  • Less stress on engine components (and the rider)

Manufacture of obsolete components to dwg or pattern

Our workshop has comprehensive turning and milling facilities and some welding and heat treatment facilities. We are happy to undertake special commissions to manufacture obsolete or unobtainable parts to your drawing or pattern.