Zongshen RX3: How the 6-Speed Transmission Operates

[SpudRider]

This thread will describe how the 6-speed transmission of the Zongshen RX3 operates.

Power Flow

Power from the crankshaft spins the main shaft via the clutch. Six gears on the main shaft are connected to six gears on the counter shaft. Each gear combination has a different ratio, which results in a six-speed transmission.

Gear Engagement

Some gears are fixed to the shaft in a stationary position. Some gears are fixed to the shaft, but they can slide laterally. Some gears are free to spin. In the illustration below, the free gears are marked with an white 'X.' You will notice that free gears are always located opposite fixed gears, and vice versa. At the moment, the transmission is in neutral. The gears of the main shaft are numbered.



If a gear is fixed to the shaft, but can move laterally, it moves along splines. The next photograph shows the splines on the shaft (A), and the splines inside the gear (B). Lumps on the gear called dogs [C] allow the gear to lock with adjacent gears.



When a gear which is locked to the shaft slides into an adjacent gear, the dogs lock into holes on the adjacent gear. Although the adjacent gear is a free gear, when the sliding gear connects with the free gear, it locks the free gear to the shaft. This is how gears are selected from the transmission. Once locked, the formerly free gears can drive the opposite gears on the other shaft of the transmission, and power is delivered to the sprocket.



Choosing a Gear from the Transmission

When the transmission is in neutral, every fixed gear is aligned with a free gear. Since the free gears spin on the shaft, no power is delivered to the sprocket. This is the situation shown in the illustration below.



However, when you select first gear, one of the locked gears on the counter shaft slides to the right, and engages the adjacent free gear, locking it to the counter shaft. Power now flows from gear #1 on the main shaft to the opposite gear on the counter shaft, and power is delivered to the sprocket.



Examine the next five photographs. In each case one of the fixed gears slides laterally to engage one of the free gears, and locks it to the shaft. Please note, when you change gears, the previous gears must disengage before the next gear can engage. Obviously, you can't have two gears engaged at the same time.











You might ask, what makes the fixed gears shift back and forth to engage the adjacent gears? If you look inside the orange ovals in the photograph below, you can see each of the shifting gears has a grooved surface which accepts a shifting fork. Each shifting fork has a knob which engages the grooves on the shift drum. As the shift drum is rotated, it activates the shifting forks which move the fixed gears, and shift the transmission.