My son dream have been to race mx he is 5,11 and 13 yars old wat should he race a 125 cc two stroke dirt bike or yfz 450 quad he doesnt care he has had both but hes a great rider on both he has a 700 raptor right now and he takes pretty big jumps he wants to race mx

 

How can he be three different ages?

Dirtbike MX seems to be more popular than quad MX. Probably safer and less expensive, too.

 

I am not sure where you are located, if your son decides to ride the quad mx he won't be able to ride the 450 if it is a AMA sanction event. They are very strict on the ages, at his age the biggest quad he could ride would be a 300 4 stroke. There are outlaw series out there that allow him to ride that big of machine but I would never stick my kid that age with adults on the same size rides. You really need to check into youth classes. Even the outlaw series have them and they are usually a 200 2 stroke or 300 4 stroke. It would be a lot safer for him.

 

throw him on a blaster and race in the 300 4 stroke class.