It appears you're interested in specifications for the BMW R50US. This Allround model is powered by a Two cylinder boxer, four-stroke engine with 494.00 ccm (30.14 cubic inches) of actual displacement before 7.5:1 compression. Fueling is metered via Carburettor. 24mm Bing allowing this machine to produce its 25.97 HP (19.0 kW) horsepower and torque. According to our records engine heat of the BMW R50US is moderated by Air. You'll need to get familiar with the 4-speed transmission and pay attention to final drive Shaft drive (cardan) maintainence. Our best information shows that the front tire size is 3.50-18.00 and the rear is 4.02-18.00 . The entire package is supported by the frame, Steel doble 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). Duplex full hub front brakes and Expanding brake (drum brake). Simplex full hub rear brakes. The BMW R50US was launched in 1968, 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.