it depends on how tall you are if your somewhere between 5.3 and 5.5 you should get a 125cc but I can ride a 125cc and im only 5.1 it just depends on how good of a rider you are.if you between 5.6 and 5.10 you should get a 150cc dirtbike.If your 5.11 or taller you can ride any dirt bike you want.
19753
Yamaha
Yes
For a 13 year old it depends on your size and your experience with dirt bikes, but an 85 is usually the best size bike and fastest for a 13 year old. Unless you are really tall which you would need a 125.
The biggest and most expensive one you can find!
Kawasaki Kx500, any year will do, but the best bike for a beginner is a Yamaha yz490
Every bike goes about 20km less than the cc's. So a 450 would go about 420km to 450km. Probably the honda. I dirt track a yz450f set up with 13/35 gearing on half mile track and get 70mph
On the roads - no. On private property - sure.
you should get a 80-125
Honda xr/crf 100 would be better.
Depends on weight/height. At thirteen I rode a 125 4stroke trail bike and an 85 two stroke racebike
It Depends on what bike your talking about. they can range anywhere from 50cc to 600cc The motocross bikes usually range from the yz250f to the 426 or the 450f.