It appears you're interested in specifications for the Derbi GPR 50. This Sport model is powered by a Single cylinder, two-stroke engine with 49.90 ccm (3.04 cubic inches) of actual displacement before 13.0:1 compression. Fueling is metered via Carburettor allowing this machine to produce its horsepower and torque. According to our records engine heat of the Derbi GPR 50 is moderated by Liquid. You'll need to get familiar with the 6-speed transmission and pay attention to final drive Chain maintainence. Our best information shows that the front tire size is 90/80-17 and the rear is 110/80-17 . The entire package is supported by the frame, . We know you like to go fast or cruise all day, but when you need to stop, you'll be dependant on Single disc front brakes and Expanding brake (drum brake) rear brakes. The Derbi GPR 50 was launched in 2004, and we're happy to know (or assume) you've got one in your garage. To help you keep your ride in tip-top shape, consider purchasing an owner or service manual.