Re: couple of questions
Anything not chinese is not worth building because it'll cost as much as a real moped ($600+). That being said, it is possible to run a reliable chinese kit (assuming you have a decent bike) for under $200. It might take a month before you get the kinks in your build out, but after that the engines shouldn't have any problems for a good while. Even if you blow one, you can replace the entire engine for $80 and use your old parts. Everything other than the engine costs about $20 tops to replace. The main thing would be distance you need to travel because of wear and tear.