what bike??

IF you have the money you could buy it from a dealer. If not ****, the classified section on this site (where i got my bike), dirtbiketrader.com, cycletrader.com all seem to be good sites.

This is what I can tell you. The kx100 is a motocross bike, and is made for jumps, and for mostly use on tracks, the crf230f is more of a trail bike, but will not be a great jumping bike........Most 2-stokes are louder than 4-strokes. Most bikes can have their seat hight changed

XR200 or the CRF 230 would be better for trail riding- you would love the e-start on the 230.

Small 2 strokes do not go slow- they want to be WFO all the time- great on a track, not so good in the woods.

Trail riding typically menas riding on trails that you have not seen before- which means the bike has to be reactive to sudden changes in elevation or sharp corners- and many times you will want to stop and think about how to tackle an obstacle- on a small 2 stroke stopping to think is the kiss of death- you have to stay on the pipe and make decisions on the fly , if you pick a bad line you are committed.

To me that is not fun, especially for someone who is just starting to ride.

I have a KTM 300 and a 620, I can actualy have a blast on my wifes slow heavy XT225. Yes the suspension is not so good but it is a lot of fun. and that is what trail riding is all about, having fun- I do not think you will have fun on a small 2 stroke - at fisrt. maybe when you are a little taller and have the reactions and skills to read the trail and keep the bike on the pipe, a 2 stroke will be a blast- but to start out a 4 stroke will be more fun