It appears you're interested in specifications for the Velocette Mac . This Allround model is powered by a Twin, four-stroke engine with 349.00 ccm (21.30 cubic inches) of actual displacement before 6.8:1 compression. Fueling is metered via Carburettor allowing this machine to produce its 18.00 HP (13.1 kW) horsepower and torque. According to our records engine heat of the Velocette Mac is moderated by Air. You'll need to get familiar with the 4-speed transmission and pay attention to final drive Chain maintainence. Our best information shows that the front tire size is 3.25-19 and the rear is 3.50-19 . The entire package is supported by the frame, Single cradle. We know you like to go fast or cruise all day, but when you need to stop, you'll be dependant on Expanding brake (drum brake) front brakes and Expanding brake (drum brake) rear brakes. The Velocette Mac was launched in 1934, 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.