Frame layout, the jig

This was the jig made with a steel RHS beam and various uprights to ensure proper placement of the wheels, steering head, etc.

The motor was tilted forward a few degrees to enable the lowest possible top tube height. Lots of effort was put toward light but strong construction. Grams mattered because our engine wouldn't have huge hp so the overall weight target was under 100kg. I estimated 60-65hp, so hp to total weight ratio target was 2.8kg per hp. The pic shows engine mock up for accurate engine/chain/frame alignments. The rear wheel is WR200 motocross hub with 36spoke alloy rim. The headstock was turned from chromoly and a lower bearing spigot is turned from heavywall steampipe.