Motorcycle chains and final drives are strong, durable, and efficient, but they do need occasional maintenance. Fortunately, these are fairly simple procedures and can be accomplished by most owners in a reasonably short time.
A quick inspection should be performed before every ride. On bikes equipped with chains, a thorough inspection, lubrication, and adjustment should be completed at least every 600 miles (approximately 1,000 kilometers) or whenever the chain links begin to look dry. Look for loose pins, damaged rollers, dry or rusty links, kinked or binding links, excessive wear, and improper chain adjustment. Also check for loose sprocket-mounting fasteners, and worn, damaged, or missing sprocket teeth.
Chain maintenance is much easier if your motorcycle has a center stand. Position it on the center stand and place the transmission in neutral to allow the rear wheel to be turned by hand. If your bike doesn't have a center stand, roll it forward a short way each time to access another section of the chain.
Chains and sprockets should be cleaned to remove grit, which accelerates wear. Most motorcycle chains use O-rings or X-rings (an O-ring with an X-shaped cross section) to keep lubricant inside. Cleaning the chain with gasoline or harsh cleaning solvents can be dangerous and can ruin the chain by drying out O-rings and removing lubrication. Clean the chain with a commercial chain-cleaning product, a rag, and a brush.
A helpful cleaning tool is the Grunge Brush, which is specifically designed to work with motorcycle chains and is available at many dealers. The replaceable bristles are located on individual pads that can be set to fit any type of motorcycle chain, making it easy to clean in and around all sides of the chain.
Clean small sections at a time by slowly turning the rear wheel to access each section for cleaning. Use a chalk or crayon mark or master link as a guide to how much you've done, and make sure there's a bit of overlap. After cleaning and inspection, spray on a coating of chain lube. Use a quality chain lube that provides superior lubricant penetration to critical roller stress points, thereby reducing friction, power loss, chain "stretch," and sprocket wear, and preserving O-rings and preventing O-ring swelling. Use the tubular spray nozzle to reach all areas and ensure that the entire length of the chain is coated.
The chain adjustment should allow about an inch to 1.5 inches of vertical movement (when lifted by a finger) along the lower section between the sprockets, measured at its midpoint. This measurement may vary among models and manufacturers, so follow the procedure in the owner's or shop manual. Typically, as a chain and sprockets wear, the chain's slack will vary more and more as it goes around, so some sections will be tighter than others. Always adjust the chain at the tightest point in its rotation. Generally you have to loosen the axle shaft nut, then turn adjusters on both ends of the axle equally. Be sure to follow the procedure in the owner's manual, paying special attention to ensure that the adjustment nuts are properly set and the axle is adjusted to the same number of reference marks on each side, so the wheel is straight. Then tighten the axle to the specified torque and replace the cotter pin. Always recheck slack, axle-nut tightness, and brake operation before riding.
Eventually, even with excellent care, chains and sprockets will wear out. The teeth on a worn-out sprocket begin to take on a hooked shape, with a deeper pocket on the side that the chain pulls against when it is under power. With the engine off, pull the chain where it wraps around the rear sprocket. If it's possible to pull the chain out a substantial distance, it needs to be replaced. A chain in good condition will only pull out a small amount.
As a general rule, when the chain is worn out, both sprockets should be replaced. Otherwise, running a new chain on worn sprockets will accelerate the wear on the new chain. O-ring (and X-ring) chains last longer than non-O-ring chains and should always be replaced with the same types.
Chains and sprockets should also be replaced with new ones that are the same size as the original equipment (for example, size 520 or 530). Some aftermarket sellers offer lighter, smaller-size chains and sprockets that are said to improve performance. However, your motorcycle was designed for a certain size based on weight and power, and lighter-weight chains and sprockets will wear faster. They are more prone to failure and sudden breakage, which could result in a crash.
If you are at all hesitant about your abilities or the equipment needed to perform any of these procedures, bring your motorcycle to a motorcycle shop or dealer to have the work done by an expert.
Shaft Final Drives
Many large touring motorcycles have shaft drives instead of chains. These typically require less-frequent maintenance, but they do need some inspections and lubricant checks and changes.
Some shaft drive systems include Zerk (grease) fittings on the drive and driven ends of the drive shaft that need grease periodically. Keeping these fittings greased at regular intervals will help ensure these expensive parts are lubed. The rear-end gear set in the rear hub runs on hypoid gear oil and the level needs to be maintained. Look for any signs of leakage, which must be corrected or the level topped up. The oil should be changed at the maintenance intervals specified by the bike's manufacturer. Always use lubricants approved by the motorcycle manufacturer.