I'm in the process of obtaining a Harley Davidson Soft Tail Frame. I will do work if necessary to get it like the Harley Heritage. I have a number of Harley gas tanks and other assorted parts. I want to configure the frame to hold a Yamaha 1700 Road Star Engine that I have. I will need to weld in new motor mounts once the engine and drive belt are completely lined up with the rear swing arm. I will add a tour pack when it's finished.
The Yamaha Engine is a twin cam, push rod engine just like the Harley's. The difference is the Yamaha Road Star Engine has ceramic liners in the Cylinders and the cam drive is all gear. The Harley's use a faulty Chain Drive system on their engines and the guides wear out at 15,000-20,000 miles, if you're lucky. This engine takes out the Oil drive and the engine grenades in a spectacular fashion. This requires an engine tear down to either replace the guides of if the engine grenades.
Harley knew they had a problem with their twin cam engines and never addressed the issues. To top it off, their bikes / Trikes with these engine cost anywhere between $ 25,000-$ 40,000 Dollars.
The Harley Davidson Evolution engine made in the 90's is widely regarded as the best Engine Harley Davidson ever made.
The Harley Frame has a wheel base of about 67 inches. With a good saddle with a back rest, this bike should be a comfortable ride with a reliable power plant.