CVT in motorcycles – rarely used so far
While CVT transmissions are standard on scooters and ATVs, they have so far hardly become established on larger motorcycles. A well-known example of a motorcycle with this technology is the Aprilia Mana, a V2 model with CVT. Despite these approaches, the breakthrough into the mass market has failed to materialize. But with more and more riders wanting to do without a clutch and gearshift, this could change. Yamaha offers a semi-automatic solution with the Y-AMT, BMW has developed the ASA system and KTM also relies on automatic shifting with the AMT. In this environment, CFMoto’s approach with a CVT motorcycle could offer a new option.
How the CVT transmission works
The continuously variable transmission works with two pulleys, each consisting of two conical halves. One pulley is connected to the engine via a centrifugal clutch, while the other is connected to the drive output, in this case a cardan shaft, via a bevel gear. The two halves of the pulleys can move towards or away from each other, which changes their effective diameter. A V-shaped belt transmits the power between the pulleys. The transmission ratio changes depending on the position of the pulleys: If the front pulley becomes larger and the rear pulley smaller, the output speed increases. If the front pulley becomes smaller and the rear pulley larger, a lower gear is created, which reduces the speed but increases the torque.
New engine with variable valve timing?
The unit shown in the patent is a parallel twin with chain-driven, double overhead camshafts (DOHC). A component on the gearwheel of the intake camshaft that resembles a camshaft phasing unit is striking. This detail is not explained further in the patent, but its shape suggests that it is a variable control for the intake valves. This could ensure better power delivery, depending on engine speed and load.
Although it is not certain whether this engine is intended for a motorcycle or an ATV – the cardan shaft could indicate off-road use – the patent explicitly names a motorcycle as the intended use for the drive.
Comparable concepts from China
Even though CFMoto itself does not yet have a CVT motorcycle in its range, there is already a similar concept from another Chinese manufacturer. Lifeng, better known under the “Regal Raptor” brand, has presented a motorcycle with a CVT transmission that is equipped with a CFMoto engine. However, this is not the unit shown in the patent, but a 963 cc V2 engine from CFMoto’s CForce 1000 ATV, ZForce 950 side-by-side and UForce 1000 utility vehicle. This engine produces 71 hp (52 kW) and has a simpler SOHC valve control system.
However, the Regal Raptor motorcycle weighs in at a considerable 355 kg (783 lbs), so despite its power, it is unlikely to deliver outstanding dynamics.
Conclusion
It remains to be seen if and when CFMoto will bring a motorcycle with a CVT onto the market. However, the patent shows that the company is working on such a technology. In a market where semi-automatic transmissions are becoming increasingly important, a continuously variable automatic transmission could be an interesting alternative for riders who want to do without manual shifting.
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