Hello all I am very new to this site and the world of Motor bicyles. I love it! I just test rode a 2-stroke cruiser yesterday. I like it, but I think I'd like to build a 4-stroke mountain bike setup. Can anyone please tell me what requiremnets I should look for to determine which mountain bike to purchase(fitting), Also Where I can find a great quality 4-stroke engine. Thanks so much, trying to build a great bike. Any help is appreciated.