Pulse Scout 49 50cc won't go over 20mph

I bought a Pulse Scout 49. It wouldn't charge the battery. So I changed the regulator and now that works fine.

However when riding the bike it will not go over 20mph. Top speed is exactly 20mph.

All else seems to work great.

Any ideas?

 

We need more info ? what have you done to it?
Belt/rollers/clutch/ carb?

 

Could be a "bicycle" restricted one for NL and Denmark etc, just the cdi rev limit that is the difference if I'm not mistaken.
25kmh is about 20mph right?

 

Could be. I adjusted the air fuel mixture and idle and it has done a few more miles per hour but thank you for replies.