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subject: Description Of Chinese Motorcycle Existing Technology [print this page]

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.

by: sunnyzx

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