Motorcycle Drive Chains

Chain drive is used on more motorcycles than drive shafts and belts. The drive system consisting of a chain and two sprockets is lightweight, efficient, and allows for easy gearing changes.

The cleaning and adjusting of the motorcycle's drive chain is one of the most overlooked maintenance requirement on any motorcycle. It's a time consuming, dirty task to clean, lube and adjust the chain.

With periodic maintenance and adjustment the today's modern O- ring chains have doubled the life time of use we get from the drive chain. Today's chains are made of stronger materials but are still subjected to the same conditions; stress from horsepower, weather, and grit. The greatest factor in the chain's life is maintenance. It is usually the lack of periodic maintenance that shortens their life spans.

Drive chains are made up of links, side plates, pins, bushings and rollers. It's the rollers which engage the sprockets teeth. Today with the advent of the o-ring chain; chain life has been extended tremendously. The o-ring seals in grease to lubricate the rollers; they also prevent water and dirt from getting in. The latest innovation is the x-ring chain; it is supposed to reduce drag while still offering the same level of reliability as the conventional o-ring chain.

Those little rubber rings have solved one of the chain maker's biggest headaches; the loss of lubricant. The load bearing pins and bushings that enable a chain to bend over a sprocket have precious little oil to keep them lubricated. With high centrifugal forces that occur when the chain turns around the drive sprocket, forces the lubricant out and of the chain. The only reason for chain wear is the loss of lubricant. With the use of the O-ring this enabled the chain to keep its oil inside and stay lubricated where it counts for longer periods of time and service.

The lubricant in a modern O-ring chain is not ordinary oil. It contains plenty of synthetic additives that help it withstand the enormous loads that develop during first-gear. Friction is not a significant issue; the lubricant's film strength is what keeps the metal from touching and wearing. The moment the lubricant is not there, wear escalates.

The chain ends are joined together by a master link. The master link may be staked, which is the strongest and safest method. A staked master link creates an endless chain which is seen on most modern sportbikes. The staked master link requires special tools to install or remove it.

The other method is by the spring clip, which can be installed and removed with a pair of pliers. Master links with spring clips should always be installed with the closed end facing the direction of travel. The spring clip can easily be dislodged if the open end comes in contact with anything that can get in its travel path.

Even the cheapest chain without O-rings will last a very long time with proper care, meticulous adjustment and oiling at 350-500 mile intervals. Heavy gear oil applied with a brush is used by many racing teams. This is a messy proposition and best only when the chain can be left to drip away the excess; preferably overnight.

Most people spray on chain lube, which is good as long as you wait the required 20 minutes to let the solvents in the spray evaporate and leave the thicker lubricant on the chain, rather than on of the tire's sidewall.

Chain grease isn't as efficient. It cannot get into the tight clearances between the moving parts and the most good it can ever do is keep the chain's side plates from rusting in the winter.

Chain oil's main enemy is high running temperatures. The running temperature of a chain should not exceed 160 degrees Fahrenheit (70 degrees Celsius). Above that, chain lubricant starts to thin and the chances of it seeping out past the O-rings increase; eventually the film strength drops.

Surprisingly an over tightened chain is far worse than a loose one. Suspension movement increases chain tension and what is a fairly tight chain at standstill becomes tighter when the suspension bottoms. These added unnecessary tensile loads can exceed the chain's capacity and the increased friction will raise the chain's temperature quickly.

The best way to check chain tension, the one used by many race teams; is too ask two of your biggest friends to sit on the bike and compress the rear suspension to the point where the wheel axel, swing-arm bearing bolt and the front chain-sprocket centerline are all in line. That is the point of maximum chain tension. Or you can compress the bike's rear end with a ratcheting tie down. Free up and down movement at the middle of the chain's bottom run should be about half an inch (13 mm) with the suspension compressed.

Your motorcycle's owner's manual will have the recommended amount of chain free play to be measured midway on the bottom run. That free play includes both up and down movement of the chain while the bike is sitting on the ground.

Of course, a loose chain is not good either. It will rub on many static parts of the bike such as the swing arm rubber buffer and frame spacers. Besides, with the chain's ability to saw through anything in its path, the added friction will again raise temperatures.

The sprockets will also suffer from a loose chain condition. A loose chain will "ride up" into the higher and weaker areas of the sprocket teeth and slowly bend them into a hooked shape. Proper tensioning as explained above is the remedy.

Also, proper tensioning means a straight and true running rear wheel. A cocked rear wheel will place uneven stress on the chain, making one side of it work harder than the other. A quick check can be made by sighting the chain's top run, back to front. A badly misaligned rear wheel will show as a notable kink in the chain's run line.

For more exact results you can pick two eight foot (2.5 meters) straight-edged wood boards and place each on either side of the bike, about 4" (100mm) above the ground. On a properly aligned wheel, the edges should touch the rear tire sidewall and leave equal gaps on both sides of the front tire. Adjust your chain tension adjuster accordingly.

Race teams use a compass with two, long sharpened points to compare the distance between the swing arm bearing pivot and the rear wheel axel; a measuring tape can be just as effective; simply measure the distance from the center of the swingarm pivot to the center of the axel. It should be the same on both sides, if not adjust the chain tension adjuster until both measurements are the same.

Even after all this straightening, it's worth checking, making sure that the chain runs centered on the rear sprocket. A missing 1mm washer somewhere may cause one side of the sprocket to make contact with the chain. If after some mileage one side of the rear sprocket gets shiny near the teeth it means that the front and rear sprockets are not properly aligned. A few shims or washers behind the drive sprocket may be necessary.

Off-road riders have a few problems all of their own. The mud or sand that gets trapped between the chain and sprocket works as a fine grinding paste, destroying chains in no time. The "relieved teeth sprockets" that are available from aftermarket supplieres help a great deal in reducing chain wear and stretch by letting the dirt out of the high-pressure area where the roller and sprocket teeth engage. Proper maintenance of a dirt bike's chain also means a good hosing after the ride, first drying and only then oiling. By the time of your next ride all the excess oil will have dripped away, reducing dust pick up to minimum.

Chains really don't stretch but as they do their job the lubricant between the pins and bushings is burned off by heat, pressure, and friction; loose enough of the chain's lubricant and rapid chain wear, takes place. As the various parts of the chain rub against each other, wear develops between the pins and rollers. With the wear, the chain elongates.

Sprockets, as a rule do not require any maintenance other than inspecting the mounting bolts and cleaning. As the chain wears and elongates (stretches), or if the chain is allowed too long in a slack condition, it will ride up on the sprocket teeth, quickly wearing the teeth into sharp hooks.

Inspecting the chain for wear is rather easy. If you have it off the bike checking it's length is one method. On the bike, pulling the chain off the rear sprocket is another. If you have too much play, or you have run out of adjustment it's time to replace the chain. When replacing the chain, the sprockets should be replaced at the same time.

Manufacturers use a series of numbers: 420,428, 520, 530, and 630, followed by a series of letters to designate type style and strength. With motorcycle drive chains the first number will always be a 4, 5, or 6. These numbers correspond to the chains size or physical dimensions.

Chains are measured in pitch. The pitch is the center to center distance between any two adjacent pins. The first number is the pitch measured in eighths. A 4 series chain measures 4/8 (1/2) inch between pins. A 5 series chain is 5/8 inch between rollers and a 6 is 6/8 (3/4) inch.

530 EK heavy duty o-ring chain

The next digits represent the nominal width of the chain between the inner plates or bushings measured in eights. A common 530 chain would measure 5/8"from pin to pin and would be 3/8" between the inner plates. These are nominal measurements; the actual dimensions can vary a little from manufacturer to manufacturer. They can also vary between chains of the same dimensions, but of a different grade or style made by the same manufacturer. The letters after the numbers are the way the manufacturer describes the special characteristics that particular chain may have.

Pitch is Pitch, a 530 chain from any manufacturer the pitch will always be the same 5/8"; as well as the roller diameter. Chain width between the roller link plates may vary slightly as well as the overall width. The plates themselves may be thicker or thinner, pin lengths will probably be different and so on.

It's pretty clear that one manufacturer's master link may or may not fit another manufacturer's chain. Using matched chain and links is the best way to insure the fit is correct and it's the correct tensile strength. Remember a chain is only as strong as its weakest link. Using the incorrect master link; a 5,000 lb master link in a 10,000 lb chain application can drive that old adage home. Never mix chain pieces or manufacturers.

Always check your owner's or service manual for recommended types of chain, or the chain manufacture's recommendations before replacing your chain. It's ok to upgrade your standard chain to a heavier duty or o-ring chain. You should never use a lesser strength chain than is recommended. It can and will wear faster and possibly stretch faster letting the chain saw away on parts of your motorcycle, or worse break, leaving you a long walk home.

Ok you're all excited about running out to the garage and cleaning, lubricating and setting the tension on your chain; but just what do you use for a chain cleaner?

Most chain manufacturers recommend kerosene, WD 40 works well and it's easier to handle and far more convenient to use. Be careful what you use to cut the gunk off of the chain with; especially if you have an o-ring chain. It won't help no matter what you use if it damages the o-rings.

Locate the master link in the chain, and mark it so you will know where you begin and end. Spray the WD 40 on the inside or the lower run of the chain as you rotate the rear wheel. You may want to use a plastic bag to cover the wheel and rim or any other parts you don't want wetted down with the WD 40. Use a rag to wipe off excess WD and dirt from the chain. Pass a corner of the rag in-between the rollers and clean the inside of the side plates and the rollers.

Do not use a wire brush of any kind to clean the chain; they can damage the o-rings. Use more WD 40 on stubborn areas and rub with a rag.

Once you have the chain nice and clean, make sure the sprockets are clean too; there's no sense in letting the grit stuck on the sprockets to contaminate the clean chain.

With chain and sprockets now clean, take the bike out for a short 15 minute ride. This will help warm up the chain. As soon as you get home spray or brush your chain lube on the inside of the chain, (That's the part of the chain that wraps over the sprockets yes the inside. Centrifugal force will push the lube into the chain as you ride). Let it stand for a few minutes. Read the label on the can for the time it will take for it to work its way into the chain. Do not run the engine or put the bike in gear to apply the lube, raise the rear wheel off the ground or push the bike forward or back to get access to the chain.

Then take a rag and remove the excess lube, do not remove all of the lube, just the excess.

Even o-ring chains need to be lubricated, any of the chain lubes will work even heavy gear oil will.

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