Also for track days fitting a smaller rear sprocket. The 2 / 3 speeder chaps fit smaller sprockets for acceleration.
You lower the gearing by fitting a smaller final drive sprocket on the crossshaft (two speeder) or to the wormwheel output (three speeder) and a bigger one at the wheel end.
Quite common for two and three speeder owners to adjust the final drive ratio to suit a given venue, but as the engine in most racing classes gives more power than standard, ratios tend to start from a higher point. One two speed racer I remember being sold had a 70mph first gear (standard is about 45).
