my 41 bhp mx 125 its been tuned by 55cctuning.com they have dun all the dyno work all the tuning the beggest power mod was the jollymoto pipe off a rs 125 it gave it 9 bhp just from the pipe it was 26 bhp when i got it.the pipe made it 35 hp then i got 34 carb- racing piston-racing reeds-twinair air fliter-bigger jets that gave it 6 bhp its very fast for a 125 it run 14.flat at york dragway with a 4.9 0/60 put aprilia mx 125 at you tube then look for prostjohnson all my vids are there tell me what you think