Introduction to Motorcycle Maintenance - Page 5

Drive Chain

Clean the chain if it is excessively dirty. Lubricate the chain if it appears dry or kinked and after cleaning it. Check chain slack (vertical free movement) after lubricating the chain, and adjust if necessary. Drive chains may wear unevenly, so you need to check the slack in multiple locations. If the chain is excessively worn (no adjustment room left or beyond the service limit, as specified by the manufacturer), severely rusted, severely kinked (not resolved with lubrication), or otherwise damaged, the chain will likely need to be replaced.

Chain slack is typically measured midpoint between the front and rear sprockets. Adjust the slack where the slack is the least. It is better to have a bit more slack (but not too much) than too little: a very loose chain may come off the sprockets and cause damage to the engine cases and frame and cause the rear wheel to lockup, potentially causing a crash. A chain that is too tight will put excessive strain on the drive train components, can cause accelerated chain and sprocket wear, and limit rear suspension movement. As the suspension compresses and extends, the chain slack varies. Consult your owner’s manual or service manual for how to measure chain slack on your motorcycle and for the allowable range. On some motorcycles chain slack is measured with the rear wheel off the ground, while on others the slack is measured with the motorcycle on the side stand.

There are a number or commercial chain lubes on the market, and I’ve tried a number of them. I prefer to use gear oil to lubricate the chains on our motorcycles. I admit it makes a mess, but it is not difficult to clean. Automatic chain oilers use it or something similar. Gear oil is not sticky like some of the commercial chain lubes, so it does fling off some, but when it does, it takes some of the grit away with it. An O-ring chain uses O-rings between the side plates to seal grease inside to lubricate the chain internally, but the chain rollers (the parts of the chain that make contact with the sprocket) still need added lubricant. External lubrication (oil or chain lube) also prevents rusting of the chain. The O-rings also benefit from external lubrication.

There are some commercial chain cleaners available, but I use kerosene and a soft tooth brush and rags. It’s a messy job, so wear disposable gloves and old clothes and protect your floor. I also use a piece of cardboard to block most of the splatter from contacting the brake disk. After cleaning the chain, wipe it well with a rag right afterwards and again after the bike has sat for a while, and then lubricate the chain. Clean the brake disk with brake cleaner before riding or using the rear brake. Clean up any other splatter with a rag.

On the majority of motorcycles with chain final drive, chain slack is adjusted by loosening the axle nut and then using the adjusters on either side of swingarm to move the axle forward or backward an equal amount to increase or decrease the amount of slack. If your motorcycle has a single-sided swingarm, then the procedure will be different. There are adjusting marks on either side of the swingarm if there are screw-type adjusters to aid in proper alignment. Some motorcycles have “snail type” adjusters which make the alignment process easy. Don’t use the snail type adjusters to move the axle as that could cause wear to the pin that the notches in the adjuster align with; instead, hold the adjuster in position and move the wheel back then forward. The adjustment marks / axle position on both side of the swingarm must be the same so that the wheel is aligned correctly with the direction of travel. The wheel should be pushed forward against the adjusters before checking the slack and tightening the axle nut. The axle is then tightened somewhat and the chain slack is checked again, and if not correct, the process is repeated. Finally, the axle nut is torqued to specification.

While you’re at it, check the chain slider (swingarm protector) and chain guide and chain guide slider for damage and excessive wear. You don’t want to completely wear through the chain slider (on the swingarm) because the chain will then cut into the swingarm.

Sprockets

Check for excessively worn or broken sprocket teeth. Replace as needed or when the chain is being replaced. The general rule is to replace the sprockets and chain as a set. The reason being that if they are not all replaced at the same time, then the worn parts will cause accelerated wear of the new parts. Note that the front sprocket tends to wear faster, and some riders will replace the front sprocket alone, and I see nothing wrong with that. The front sprocket is usually the easiest and least expensive part to replace: neither the chain nor the wheel needs to be removed on most bikes in order to replace the front sprocket. Some riders also swap front sprockets back and forth to change the final gearing for different riding situations; this is more common among dual sport riders.

If the chain needs to be replaced, then replace the sprockets at the same time. If you're only replacing a single sprocket, and the chain still has lots of "life" in it, then I wouldn't replace the chain (under normal use) at that time. However, if you need to replace a sprocket, and the chain has worn significantly (has required a lot of adjustment; doesn't have many km left in it), but even if it still has some "life" in it, I would replace chain and both sprockets.

Drive Belt

Refer to your owner’s manual or service manual for maintenance information.

Drive Shaft

Refer to your owner’s manual or service manual for maintenance information.