⛓️Drive chain

How it works

The drive chain (or final drive chain) transmits power from the gearbox output to the rear wheel. It's the most common form of final drive on motorcycles (ahead of belt and shaft drive): light, efficient, and inexpensive, but it demands regular maintenance. The chain wraps around two sprockets: the front (countershaft) sprocket, small, and the rear sprocket (or "crown"), large; the ratio between their tooth counts sets the final drive ratio. Modern chains use O-rings (or X-rings): small rubber seals that trap factory grease inside each link, which greatly extends their life, provided you don't attack them with harsh cleaners or a pressure washer. Failure and wear modes: stretch (pins and bushings wear, the chain "lengthens," and the tension you adjust keeps coming back), stiff or seized links (neglected lubrication, dead O-rings), hooked, worn sprocket and rear sprocket teeth, and, in the worst case, the chain jumping or snapping. A chain that's too slack rattles, causes jerky power delivery, and can jump off; too tight, it strains the gearbox output and wheel bearings. Chain, rear sprocket, and front sprocket wear together - all three are replaced as a set (a "chain kit"). Signs: clattering from the rear, jerky power delivery, vibration in the higher gears, excessive play. Chain slack (vertical deflection) is often on the order of 2 to 4 cm depending on the model - check your manual.

Maintenance tips

• ✓Check and adjust chain tension regularly (often every 500 to 1,000 km, and after riding in the rain), at its tightest point, with the wheel aligned, to the slack figure recommended by the manufacturer. A chain that's too slack rattles and can jump; too tight, it wears the bearings.
• ✓Lubricate the chain often with a dedicated chain lube (ideally while the chain is still warm from a ride), on the inner run while turning the wheel, then wipe off the excess. A dry chain wears out very quickly.
• ✓Clean the chain with a mild, suitable product (never an aggressive solvent or a pressure washer, which destroy the O-rings) and a soft brush before relubricating.
• ✓Check rear wheel alignment at every adjustment, using the marks etched on the swingarm (matching on both sides): misalignment wears the chain and tire at an angle and degrades handling.
• ✓Watch for wear: if you can pull the chain away from the back of the rear sprocket enough to expose a tooth, or if links stay stiff despite lubrication, replace the whole kit (chain, rear sprocket, front sprocket).
• ✓Always replace the chain, rear sprocket, and front sprocket together (as a kit): fitting a new chain on worn sprockets ruins it quickly. Choose the correct pitch and tooth count.
• ✓Retorque the rear axle nut to the manufacturer's spec after every tension adjustment, and refit the cotter pin or nut lock.