Don't mean to argue (as I know very little on this) but would a 100/125 be powerful and big enough?
My brothers PW80 YZinger's can't go trail bike riding (too small, not enough power) and his 85 small wheel can't either (same deal). We just can't get up the hills due to the huge rocks! Pain in the arse pushing them (not to mention embarrassing :P).
Mates 225 can just handle it, not enough power as it is old.
Will a 100/125 be powerful enough and bike enough for riding? How long would it be before I need to upgrade because I get bored of the power? My brother is looking at getting a 125 this Christmas and he is only 13!
Ohhh, being able to double as a farm bike would be great since I am getting into agriculture!
ETA: I also read 125s only have good top end power. Could that pose a problem on these trails? They are pretty steep, steep enough that I can't push any of my brothers bikes up (including the PW80s).
ETA2: I would actually like to change my preference to a 4 stroke, 2 strokes being loud might piss my neighbours off and there is nothing worse than neighbours who make too much noise!