I don't know how long it took exactly to build this thing. My son came over with a Lawn Boy verticle shaft engine that he had converted to run as a horizontal shaft by rotating the carburetor 90 degrees. He wanted to mount it on this same bicycle. Because the Lawn Boy had starter issues, no cooling shroud and no throttle control, the brush cutter engine was used. This was mid-June. It was completed to it's current torque converter drive by July 3rd. From conception to finish, not more than four weeks. The original torque converter and chain and sprocket came from a Go-kart we had on hand. The brush cutter had engine, hand grips, throttle lever, kill switch and wiring and disconnects that were used with little modification. The thing that was most difficult was adapting the crankshaft to the torque converter. The crankshaft PTO snout was cut off of a 5hp Briggs and Stratton and welded to a 3/4-10 nut. I used a dial indicator to check runout as I welded it on. The engine is on it's second mounting configuration, but 1/8"x1-1/2" steel strap was welded to the bicycle thin wall tubing in both cases. The frame's down tube was clearanced for the engine by sawing a wedge shaped angle from the lower side of the tubing and welding it back together. A 3/8" steel plate connected the verticle gap and provided a place to mount the "foot pegs". The jack-shaft was also pirated from the go-kart, but a 19mm "sealed bearing" kit was used on the bottom bracket and through it runs the 3/4" keyed shaft. The rear seat mount and kick stand came fom an old 1970's JC Penny's 10 speed. It also has an innovative push-pull twist grip shifter that I may adapt for throttle use. The right chain stay had to be clearanced for the new chain position.
If I can figuire out how, I'll post video. I have a digital video camera, but I don't know how to load it to the computer.
Steve Gibson