I just bought an 80cc engine kit off of ebay for $174 which wasn't bad. I'm building up the bicycle right now. My engine will be here in four days. I'm using a schwinn typhoon frame and a bunch of parts off of everything else. I'm use to working on bicycles because I restore schwinns and have tons of parts and bikes to work with. I bought the kit because it's the most affordable motorized thing on two wheels I could find and I could use my bike building skills. I'm gonna make it look kinda like an old bobber/cafe racer.