RFD - 3rd Stage

The 3rd Stage of the RFD X-bike design was to CAD in the engine and transmission. The engine is a 1975 2.0L Porsche 914. For the unfamiliar this is an air cooled horizontal opposed 4 cylinder. The transmission is a Porsche 901, 5 speed with an integral differential. Above is an image of the CAD model I made for both the engine and tranny combination. The CAD solid model allowed me to configure a bracket system that would fasten the swing arm to the tranny. The trick was to design the bracket for maximum rigidity yet make it reasonable for R&R. The above image shows an early CAD model for the bracket, note that the right (blue) swing arm intersects (conflicts) with the wheel/tire indicating the need for a wide swing arm yoke or a right side offset swing arm yoke. I elected for an offset style. I remember seeing other people's custom designs where the swing arm yoke is widened on both sides to I assume maintain symetry, but I don't like that look and as it turned out a 2" offset would be plenty for wheel/tire clearance as well as drive sprocket alignment and clearance. So I just added a 2" X 2" square tube on the right side of the swing arm. Just had to measure, cut, weld and grind a bit more than if I went wide and I was real pleased with the outcome.