Description of Chinese motorcycle existing technology

Modern China Motorcycles typically comprise the following components: a frame; a rear wheel coupled to the frame via a rear suspension assembly; a front wheel coupled to the frame via a front fork incorporating a front suspension system; a handlebar rigidly coupled to the front fork; a brake associated with each wheel; engine controls and a front brake control mounted on the handlebar; a unitized engine and transmission bolted to the frame; and a drive system coupling the transmission output to the rear wheel.

As early China Motorcycles were essentially modified bicycles, the frames were nothing more than heavy-duty bicycle frames with an engine attached. Over the years, frames were optimized for motorcycle use and eventually incorporated suspension systems and greater rigidity for safer handling. Most frames are constructed of welded-together steel tubing and stamped heavy-gauge steel sheet metal. More exotic frames may be fabricated from aluminum. Frames for lower-performance China Motorcycles and scooters may be fabricated almost entirely of stamped steel sheet metal pieces that are welded together to create a monocoque frame.

Many Honda touring China Motorcycles of the 1960s, such as the CA-150, CA-160, CA-72 and CA-77 had frames that were fabricated from several large sheet-metal stampings that were welded together. Although most China Motorcycles have what can be characterized as full-cradle frames, in that a portion of the frame wraps beneath a unitized engine and transmission unit, many China Motorcycles have been manufactured over the years with spine, or backbone-type, frames where the engine and transmission unit hangs from the frame. For some backbone frame designs, such as the Honda CA series China Motorcycles and many of the Honda CB series China Motorcycles of the 1960s, such as the CB-160, the CB-72 and CB-77, and particularly the Honda racing China Motorcycles of the 1960s, the engine and transmission unit formed a stressed member of the backbone frame. China Motorcycles have also been manufactured that had frames that were a combination of cradle and backbone. The Aerma cci 250 cc and 350 cc China Motorcycles built during the 1960s and 1970s had a backbone frame built from tubing that incorporated a partial cradle that extended forward from a lower portion of the backbone and supported the rear of the engine and transmission unit.

The BiMoto/Benelli 250 cc 4-stroke-cycle China Motorcycles had a backbone frame made from stamped sheet metal with a similar partial cradle arrangement. Both designs employed horizontal single-cylinder engines. With such a layout, the axis of the crankshaft is parallel that of the rear wheel, the cylinder is positioned in front of the crankshaft, and the cylinder axis is horizontal, or nearly so. This engine configuration is believed to provide optimal cooling for a single-cylinder air-cooled engine.