Like highlandsflyer said, do you mean a
trials bike?
A trials bike and a trail bike are two different animals - a trials bike is designed to be ridden in observed trials, where you have to ride an observed section and are marked according to whether you accomplish this without dabbing or not. 1 point for 1 dab, 2 for two dabs, 3 for anything more than that, provided that you maintain forward motion relative to the section and stay within the section markers.
Plus a 5 point penalty for a fail, which can be stopping (including feet up stops in a trial run under no-stop regs), going outside of section markers, leaning on a tree or bank, that sort of stuff.
Can be used for trail riding, of course, (as long as you don't want to do much road work) and where they can go is only really limited by rider ability - if you are good enough you can basically get to pretty much anywhere, plus you don't have all those lights and indicators and other crap to break.
Anyway, some good trials video footage here on
Trials Central. This is World Round stuff, so not no-stop.
Watch the Dougie Lampkin ones - you can see (and hear :roll: ) his minder Jim Lampkin giving him line advice......
A trail bike on the other hand is now usually an enduro-styled bike (but without the performance) and with indicators, pillion footrests and that sort of stuff. Often all looks and not much else IMHO.
I was a trials rider from when I was 16 to about 42, but I haven't done anything for the last 16 years . I still think about getting something again like a 320 Majesty or 280 SWM and doing some twin-shock trials.