17
In Irelnad, and in the new year ( 2013 ) you must be 18 to be able to ride a 250cc motorbike, and must do (IBT) modules 1,3,5 on a A2 type motorbike and then take a practical driving test. If you already have your A1 liences you just have to do module 5 on a A2 type motorbike.
16 years and 250cc
17 years and nine months for a learners permit in Victoria
16 for a 50cc, 17 for a 125cc - 250cc, 21 for any cc
You are allowed to ride any size you wish as long as it's street legal. IF your under 16 then you are limited to 250cc motor.
I think its sixteen or eighteen
No age restrictions for a child to ride on a motorcycle in the U.S. Georgia
The minimum age to apply for an instruction permit for a motorcycle in the state of Texas is 15 years old. This is the youngest age to ride a motorcycle in this state - however the driver may only ride a 250cc motorcycle until their 16th birthday.
9
16
You can ride a 50cc at the age of 16 if you have a CBT which costs around £90. The bike also has to be restricted to 30 mph but most people illegally de-restrict them.