I started with a two stroke Flying horse 80cc. and have beating it for over a year. I bought it with the sole intention of seeing just how durable these little engines are and i have to say I am pleasantly surprised. I would not put it on the shelf yet. I live about 15 miles from the nearest store and about 5 miles from my nearest neighbor. So these things will cover some ground at a pretty good clip. I ride my Mtn. Bike everyday and still am using the original set-up. I would suggest starting with the 2 stroke then graduate up to the 4 stroke. Just my opinion. Opinions are like A**holes everyone gas one some just stink more than others.
and I have this....HT 6v Charging System w/- ground - MotoredBikes.com: Motorized Bicycle Forum
these....BIKE LIGHT 500 Lumen "Mt.Bike" for under 10 bucks by Veggiecycle
If you have any questions feel free to ask. Here's a pic of my Mtn. Bike prior to lighting.