It appears you're interested in specifications for the Yamaha RX 125. This Classic model is powered by a Single cylinder, two-stroke engine with 125.00 ccm (7.63 cubic inches) of actual displacement before 6.9:1 compression. Fueling is metered via Carburettor. Mikuni VM24SH allowing this machine to produce its 13.00 HP (9.5 kW) horsepower and 13.34 Nm (1.4 kgf-m or 9.8 ft.lbs) torque. According to our records engine heat of the Yamaha RX 125 is moderated by Air. You'll need to get familiar with the 5-speed transmission and pay attention to final drive Chain maintainence. Our best information shows that the front tire size is 3/0-18 and the rear is 3/0-18 . The entire package is supported by the frame, Painted tubular steel. 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 Yamaha RX 125 was launched in 1979, 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.