I just picked up my bike from the welding shop where it had been for 2 months (in which time they had done nothing) and I'm bringing it to a new shop next weekend. My design is almost exactly like this: http://www.vintageprojects.com/mini-bike/Power-Bike-plans.pdf except I'm using a Briggs and Stratton 5s that I'm thinning down by cutting off all the fins on the flywheel and I'm going to use a thin rope sheave from a Chrysler outboard that I had lying around. I'm also going to put on board track style handlebars and have the seat moved back so I'm almost sitting on the tire. I also put a really cool exhaust on with steel pipes that amplifies the sound of the engine! I would post some pictures, but I don't know how...