baja 6.5 go kart i need info please

i just picked up a baja 6.5 hp one seater gokart. the motor looks like a honda OHV motor. but it has no name on it ! any way i got it for my son for christmass i took it for ride and it i think i hit 40/45mph i was told top speed was 25mph am i just that old or was the info wrong ? because when i was 10 years old my dad got me a gokart from sears it was the 2 seater (lime limo) 4 hp gokart and that gokart did about 25mph with me and my bro on it. any one know how fast this gokart is ? and can it be slowed down alot till he grows into it thanks for any info Eddie

The motor is a china made Honda Clone. As for the top speed, it just depends on the model due to gearing. There should be a limiter nut and bolt near the throttle pedal.