gprracing

I have the new derbi gpr 50 2004 racing with the exhaust under the seat!! setup: 71cc Polini Evolution, crankcase modifyed, Polini reedvalve reeds, Kundo KRD racing crankshaft@mk prorace bearings, Malossi 26mm carburettor kit with k&n airfilter, Malossi GP MHR exhaust, Newfren racing clutch, Top Performances CDI, 15:53 sprockets, stage 6 rev. counter,