It appears you're interested in specifications for the Polini 910 GP4 Air Junior. This Minibike, sport model is powered by a Single cylinder, two-stroke engine with 39.69 ccm (2.42 cubic inches) of actual displacement before 14.0:1 compression. Fueling is metered via Carburettor. SHA 14-14 allowing this machine to produce its 4.20 HP (3.1 kW) horsepower and torque. According to our records engine heat of the Polini 910 GP4 Air Junior is moderated by Air. You'll need to get familiar with the transmission and pay attention to final drive Chain maintainence. Our best information shows that the front tire size is 90/65-R6.5 and the rear is 90/65-R6.5 . The entire package is supported by the frame, Latticed tubular 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 Single disc. 130 rear brakes. The Polini 910 GP4 Air Junior was launched in 2007, 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.