Re: Deciding on a 2 stroke kit
Well as has been said before they are pretty much hit and miss. I, like a lot of people, would suggest you buy one from a vendor that has a good warranty. (Check out the site sponsors.)
I would check out thatsdax, if you really need a 48cc they would be called f50s.
You could almost certainly get away with having a 66cc engine if you are a bigger guy and need more torque (or are pulling lots a cargo) They really don't go much faster at stock gearing and they can really make a difference going up a hill.
Last thing would be to make sure that the engine fits in the bike before you buy the engine. If it doesn't and you don't have the option of getting another bike then it would be time to look at other options.