My son is riding a CRF 50. He is 5 years old and this is his second season riding and feels ready to try racing. I am a little confused over what class to enter him into. In my district there is oil injected 50cc 4-8 yo. This seems to include mostly PW and JRs. Can he race his bike in this class? Also there is 50cc stock 4-6 yo, but this class seems to be full of KTMs and Cobras. Can anyone clarify?