I think it's fine as it is for a starter machine.
As your son's riding skills increase, then you may want to do something. Untill then, it's not the motor going to restrict him.
Most motor builders are busy now that it's race season so a month prolly isn't enough anyways.
2000 GNC 5N\
2001 GNC 9N \ 40+ class
2004 GNC 9N /
2014 rock crusher "GO tortoise GO!"
2016 Byrd Rooster
Father of the "11" time National champion,and worlds fastest woman ATV racer
A few fast LT80's
250R~300cc's
300ex
350 Rancher
Kymco Mongoose
Survivor of the 12 Hours of ATV America 04 and 05