A very small bike
Yeah if they have the right size dirt bike and gear
It depends on the size of the 11-year old!
a 120cc dirt bike is suitable for a 17 year old
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.
between 150cc and 250cc
100.
In the UK - 49cc or less.
If he needs a regular bike, I would get him a full size 26 inch bike. He is at the point where he is about to start his adolescent growth spurt.
I would perfer a Honda CRF 50 there a very great 50cc training bike
As long as you have a valid motorcycle license you can ride any size bike at any age.
an 80cc dirt bike all of the BIG 4 make them