I really don't know anything about bikes or motors so I'm pretty much a baby with this stuff. 1. are bike kits from ebay (china) crap? A couple of people on youtube said they were. If they are not all crap, how do I know which ones are good ones? 2. what does 2 stroke and 4 stroke mean? 3. Is there a thread on this forum that goes through the step by step process of installing the bike kit with a lot of pictures?