Here is my friction driven bike me and my dad built over the course of a week, all info can be found in the General Discussion Section under "Motorized Bike Build". The Engine is 30CC Ryobi Weed Wacker engine and it goes so well, about 25-30mph. The spindle is 1 1/4 inches in diameter and was made on the lathe by a friend of my dads. So here's the pics, enjoy!
From Brendonv
From Brendonv