That was a nice article --- very helpful. But here's a question from someone who wrenches and rides vintage bikes. My daughter's used XR100 cost more than any two of my own three bikes (not counting parts and rebuilds, of course). She learned to ride it cautiously, but progressively. She really fit right between the two images you pictured, Karla. She never got mad, but never got intimidated either. She just got up and got back on.
She's 13 and 5'1", maybe 125-130lbs of almost all muscle under some feminine curves replacing baby fat. She's got good sized bones and broad shoulders for a girl, and did gymnastics since she was three (she was really kind of big for a gymnast and gave it up). She rides the XR with spirit without exactly pushing it to it's limits. She thinks she want's a KX85, and there's a used one I've looked at --- but I've been stalling, thinking she at least needs a big wheel with the 16" rear and 19" front of the XR, but better suspension.
She won't touch my KDX175 or a newer 125 because of tha saddle height. But, I just bought a 1975 Yamaha MX400 (for myself). I'm still sorting out some stator/CDI issues, but she seems to want to ride it. The saddle height is pretty low --- a first generation monoshock --- maybe 33"? Her feet will touch the ground.
But heck! It will have low end (I have two other 400s of a little newer, taller variety), and some smoothness, until it hits the pipe --- then it's wheelieville and real adreneline. It isn't a punch. It's a long puuuuunch!
Do I let her ride it just because she's willing, and because she is so methodical by nature? Part of me will glory in her taking to it and mastering it. Or do I let the protective Dad part of me keep her off it because I don't want to see her crash and burn at 60mph?
What do you ladies think?