It appears you're interested in specifications for the Yamaha YAS1. This Classic model is powered by a Twin, two-stroke engine with 125.00 ccm (7.63 cubic inches) of actual displacement before compression. Fueling is metered via Carburettor allowing this machine to produce its horsepower and torque. According to our records engine heat of the Yamaha YAS1 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 2.25-17 and the rear is 2.50-17 . 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 front brakes and Expanding brake (drum brake) rear brakes. The Yamaha YAS1 was launched in 1971, 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.