The system used in motorcycles consists of three parts: the engine, wet clutch, and gearbox. All of these parts are situated in one unit which means that just one type of oil is required. Unlike dry clutches, wet clutches are covered in oil due to the single system mechanism. This also allows the clutch plates to cool down and be quiet during idle periods. Rymax offers mineral, synthetic, and fully synthetic lubricants in various grades such as 5W-40 and 10W-60.
But for scooters, it is quite different as they rely in general on CVT (Continuously Variable Transmission) which is housed separately from the engine. This means that they do not work on the basis of a wet clutch system. They are generally referred to as dry clutch. The most common type of CVT is a V-belt system which runs between two variable diameter pulleys. The V-belt runs between these two halves, so the effective diameter of the pulley is dependent on the distance between the two halves of the pulley. Based on the picture below, CVTs can change seamlessly through this system with a constant RPM in the shift.
Two different lubricants are used in this system, engine oil for the engine and gear oil for the CVT. This is also primarily why Rymax offers a different type of scooter engine and gear oil than for motorcycles. The Rymax Gevitro GL-5 SC and Gevitro GL-5 SC FS are exclusively made for scooter gear oils. For 4-stroke scooter engines, a 5W-30 and 10W-40 grade engine oil is offered. The presence of CVT means improved fuel economy to the scooter due to its lightweight system. They enable the engine to run efficiently while maintaining constant angular velocity over a range of velocities.
JASO T7903 has established two types of performance levels for this reason: JASO MA for motorcycles with a wet clutch system and JASO MB for scooters that require friction modifiers.