That is peaking at 5000RPM. Is this because it is measured at the wheel? The add says it peaks at 9500RPM:
DIRTMAX AVENGER 150CC 16HP ENGINE PITBIKE - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 11-Feb-08 12:49:44 AEDST)
And I notice it has...