I have a NRG MC3 2005 a/c. Tuned pretty well, and hits a nice speed. Got clocked doing 55mph on a straight next to my mates derbi gpr125. And it was sitting at 8000 revs out of 12k. It slowly crept up to near the 60mph mark, and then ran out of road. do they come with rev limiters? Or is the bike just going flat out and only able to hit 8k revs? Thanks