I have been debating starting a motor bike project for sometime now, but I keep running into the problem of what one to put on my bike. I have read and read and reread the problems with the China-girl, and given my limited space on the bike frame will not be going this route. I believe the 4 stroke engine is where I will be going for my build. The bike I am using is a schwinn link, not a great bike but I am not looking to do 40mph either. So this leaves me with 2 options either a friction drive or a rear mounted chain drive. Now the friction drive I kind of like, but I am very worried about tire wear. I have read that with a friction drive you have to change out your tire a lot more often, not a fan of the idea. I realize in any of these builds maintenance is needed. This leaves me with a rear chain drive setup. I have not seen many of these type, and the only place I have seen from my searches is through dax. When I go to the site I see the one for the friction drive setup, but not for the chain version. This concerns me that either they are no longer in stock or no longer made. Mostly I am doing this as I like to ride my bike, but sadly age has done a number to my knees and long enjoyable rides are hard on me now. I want it just to cruise and enjoy the ride as my need to go fast days are well behind me (near 200 mph in a drag car that threw a drive shaft scared me enough lol). Any all help would be great because at this point I am lost. Oh one more small question on either friction or rear chain can you mount a gas tank on the bike rather than the stock plastic thing they come with? I think this is long enough for one night, be well be safe, but most importantly have fun!