I ran across these
rubber motor mounts and ordered a few. They are 1/4" X 20 threads; male on one side, female on the other. I removed the motor mount studs from the engine case and re threaded the holes with a 1/4" X 20 tap (no drilling required). The male studs on the rubber mounts will then thread in the newly tapped holes nicely. I bought a length of 1/4" X 20 "all thread" and made new studs which screw into the female side of the installed rubber mounts. Next, slide the aluminum motor mount block over the new studs and mount to the seat tube in the usual manner. My first attempt utilized both front and rear mounts but resulted in too much engine movement. I wound up attaching the front mount in a normal manner on the down tube (using old inner tube rubber around the tube, and used the new rubber mounts on the rear (seat tube). The result is less vibration but not as vibration free as I had hoped. Also, the chain will rub very slightly on the left rubber mount for a few miles until it "wears in". This mod works fairly well, is cheap and easy to install, and looks like it was made for it. tools needed: 1/4 X 20 tap, and hacksaw (for cutting all-thread). Also, a couple nylon insert locking 1/4" X 20 nuts will be needed.