Yes, there are motorcycles with two-wheel drive (2WD) systems. While most motorcycles are traditionally rear-wheel drive, there have been a few experimental or specialized motorcycles designed with two-wheel drive capabilities. Here are a couple of examples:
Christini AWD (All-Wheel Drive) Motorcycles: Christini is a company that has developed all-wheel drive motorcycles. Their 2WD system consists of a front-wheel drive hub motor that transfers power to the front wheel while maintaining the conventional rear-wheel drive. The additional power to the front wheel provides increased traction and stability, especially in off-road or challenging terrain.
Rokon Trail-Breaker: Rokon is a manufacturer that produces off-road motorcycles specifically designed for rough terrains. Their Trail-Breaker model features a unique two-wheel drive system. It uses a combination of a traditional rear-wheel drive chain system and a front-wheel drive system powered by a belt drive. The front-wheel drive provides additional torque and traction in off-road situations.
It's worth mentioning that motorcycles with two-wheel drive systems are not as common as their rear-wheel drive counterparts. They are typically specialized and intended for specific off-road or challenging riding conditions. Most mainstream motorcycles on the market utilize rear-wheel drive as it is generally sufficient for most riding scenarios.