When searching for a new used bike you will notice MX bikes are substantially less expensive than Woods bikes. MX bikes tend to see a lot more revs in their life than an equivalent woods bike. Go to an MX track and listen to the racers ring out the bikes. Now go to a trail ride event and you will find woods riders riding a lot lower in the rpm range. Therefore the MX bike is a lot more worn with equal hours of use. Also you can buy a new plastic kit for approximately $150 and turn and old beater into a pretty snazzy looking scoot with minimal outlay. When in doubt when buying a used bike, make the deal contingent on the bike passing an inspection by the local dealer. A leakdown test will give you a good idea of the state of the motor before you buy it.