Streetmaster | Vision & History

Engine Modifications

The prototype Streetmaster motorcycle has a highly modified engine, designed to increase usable power, in the most reliable manner possible. All modifications were made with a mind to develop and sell kits to modify the 790cc, and 865cc Bonneville and Thruxton engines.

Streetmaster anticipates offering kits in three different steps.

1) High performance head/carbs,

2) Increased compression step-up

3) Bigger bore versions of steps 1 & 2. Ignition and exhaust packages will work on any of the versions.



All development has been conducted using 39mm Keihin flat slide carbs. Testing has proven this to be the optimal size for the reworked heads. This is an integral part of the higher flowing head, and electronic ignition listed below.

Cylinder Heads

Streetmaster has subjected stock Triumph heads to flow testing and has optimized its configuration for flow volume, velocity and valve sizing. The result is a head that approaches a 25% improvement in efficiency.

The head development has also lent improvements in cam profiles that increase lift and duration.

Heads will be offered using stock heads provided by customers on an exchange basis.

Pistons & Rods

To maximize reliability current engine modifications utilize stock pistons and rods. Streetmaster is currently in development of high compression pistons from CP and hi-performance connecting rods from Carrillo.


Stock flywheels are heavy and do not provide the ability to alter or adjust ignition timing. Streetmaster has adapted MSD brand ignition units to work with lightened flywheels with a capability of varying timing by over 30 degrees. The result is a much more responsive and higher revving unit.


The exhaust is a low restriction, two -into