Drive Unit Parts


Tires are the only part that touch the surface of the road and will 'wear', and therefore loose performance, during normal operation. When tires wear out and degrade, their ability to grip the road decreases. Once tires reach their wear limit they must be replaced for continuous safe operation of the vehicle. Periodic inspection includes keeping the tires inflated to the proper recommended pressure and checking and replacement when the wear limit is reached or there are signs of damage from road debris.

Drive Chain & Sprockets (Chain Drive Systems)

Some models use a link-type drive chain and sprockets to transmit drive power from the engine to the rear wheel. These parts are always under a large load while driving and wear during normal operation. The service life of the chain and sprockets is dramatically reduced by improper maintenance and continuous abrupt throttle operation, which increases shock loads on the drive chain and sprockets. Periodic inspections include lubrication and adjustment of the drive chain freeplay, and checking normal wear and for signs of damage. The chain needs replacement when it reaches the wear limit outlined in service literature. The sprockets also wear during normal use. In normal circumstances, the replacement interval is to replace the sprockets every other time the drive chain is replaced.

Drive Belt (Belt Drive Systems)

Some models use a drive belt and toothed pulley instead of a drive chain and sprockets. And even though a drive belt requires less maintenance than a chain, it must still be periodically checked for proper tension and wear. A special tool called a tension gauge is needed to properly check and adjust the drive belt tension. And if missing teeth or cracks are found during inspection, the belt needs to be replaced. If foreign matter or gravel gets between the drive belt and pulley teeth, the pulley may become damaged, so also inspect the pulley at the same time you inspect the drive belt.

Final Gear Oil (Shaft Drive Systems)

Some models use a shaft drive system to transmit engine power to the rear wheel. This system uses special final-drive gear oil to lubricate the drive gears, and like engine oil, must be periodically checked and replaced to remove contaminants and to provide proper lubrication. If there isn't enough final gear oil, or if the oil is degraded, drive power loss may occur, or the gears may wear out prematurely. For example, the maintenance interval for the VMAX is to inspect the final gear oil every 4000 mi (7000 km) or 6 months (fill if there isn't enough oil), and replace the oil at 600 mi (1000 km) or 1 month initially, then every 16000 mi (25000 km) or 24 months thereafter.

Weight Rollers (Scooters)

Scooters with belt-drive CVT systems have weight rollers that allow the unit to maintain a variable speed by continuously moving a pulley system to create different diameters. For this reason, the weight rollers rotate against the pulley and will wear out over time with normal driving. As the weight rollers wear out and become smaller, the proper drive ratio cannot be properly changed, which causes a decrease in acceleration power and maximum speed. The wear of the weight rollers cannot be visually inspected from the outside, so they should be replaced when the V-belt is replaced.

Air Cleaner Element for the Belt Case (Scooters)

There is an air filter that cleans the incoming air to cool the drive belt, which is separate from the air filter that filters the engine air. The purpose of the filter is to prevent gravel and other foreign material from getting caught in the V-belt. During normal use, this filter gets clogged, and the cooling efficiency decreases, and extra heat causes the accelerated V-belt wear. For this reason, this filter needs to be periodically checked and replaced.

V-Belt (Scooters)

Most scooter models use a belt-drive CVT that has a rubber V-belt to transmit engine power to the rear wheel. In the CVT V-belt system, the engine power is transmitted via pressure between the sides of the V-belt and the pulley faces. This is different from the toothed drive belt on a Star motorcycle, which transmit power using the matching 'teeth' on the belt and pulleys. As the V-belt wears it becomes thinner, and therefore the actual drive ratio changes and does not transfer the drive force correctly. Also, the V-belt is inside the belt case, so it is difficult to visually inspect for V-belt wear. For this reason, the V-belt needs to be replaced according to the replacement distance listed in the Owner's Manual.

Transmission Oil (Scooters)

Scooters use transmission oil to lubricate the transmission. When transmission oil degradation progresses, drive power may be lost, gears may wear out, and/or there may be abnormal noise. The targets for replacing the transmission oil are 600 mi (1000 km) or 1 month initially, and then 6000 mi (10000 km) or every 12 months after that.