May 1, 2015
By Bob Gregor
The rear drive chain is both the most important and most neglected maintenance item on motorcycles. At least half the bikes that arrive at our shop need chain service or replacement. On my monthly ride with the VVMC I am surrounded by the sounds of sloppy chains banging off chain guards and swing arms. Badly adjusted or worn chains can wipe out a set of good sprockets in just a few hundred miles. And it can get worse ... premature transmission bearing failure, busted cases or even a nasty crash. I was riding with a buddy up PCH back in the '80s when his Kawasaki Z1 launched a worn out chain right back into the windshield of a Porsche ... and he couldn't run because he had no chain.
First step to inspecting your chain is to get the rear wheel off the ground so it spins freely. If you have a center stand, no problemo. If not, you will need to figure out another way to support the bike.
My favorite technique is to steal the scissors jack out of my ex-wife's car and put it under a muffler or frame member (don't use the swingarm) on the opposite side of the bike from the kickstand. You have created a very stable three-point support system ... the front wheel, side stand and jack. You can put a piece of wood between the muffler and jack to protect the chrome.
You can also use a motorcycle/ATV jack from Sears or Harbor Freight. These can be tricky to use on some bikes. You might need to use a piece of wood to help even out the support. Don't forget to use tie downs.
If you are IQ-challenged, feel free to use a milk crate and hope to hell it won't collapse or the bike doesn't fall over on you.
Slowly spin the rear tire and wipe the chain clean with a rag to get a look at the condition. Now make sure that is passes freely over the rear sprocket, with no kinks or jumping off the bottom of the grooves between the teeth. Next take a very close look at the rollers and side plates for cracking or other damage. If you have an O-ring chain make sure the O-rings are intact.
The last test is to hold the chain against the rear sprocket with your fingers in two spots about four to five inches apart. Grab the chain right between the two holding points with your other hand and see how far you can lift the chain off the sprocket. If you can pull it more than about half the distance of sprocket tooth height, you need to fork out for a new chain.
When inspecting the chain, also take a look at the rear sprocket and the front if you can easily get to it. The teeth need to be symmetrical. When a chain stretches it starts wearing down the back side of the sprocket teeth.
Pull out the owner's manual and see if the chain adjustment procedure is done with the rear wheel supported or on the ground. Also look for the chain free play specification. This is generally around 3/4 inch for a twin shock bike and an inch or more on a mono shock machine. It's important not to guess ... use the exact spec.
Now slowly spin the wheel checking chain tension halfway between the front and rear sprocket. You want to do this about every six inches. Once a chain starts to get some wear, it will develop tight and loose spots at different places along the chain. At this point grab a ruler so you can measure the actual free play. You need to find the tightest spot. This is where you will position the chain to make your adjustment.
Loosen the rear axle nut and use the chain adjustment mechanism to get the specified free play. Check your manual to see the correct procedure for your bike. Bikes have adjustment marks on each side of the bike stamped into the either the swingarm or the adjusters. You need to keep them equal on each side to ensure the chain and rear tire run true. The adjusters are normally fairly accurate, but there are methods for checking their accuracy, which we will cover in a future article.
Once you have achieved the correct free play in the tightest chain position, tighten the rear axle nut and check the free play again to make sure it hasn't changed. For a final test, once again rotate the chain slowly checking the free play every four to six inches. This time you are looking for the loosest spot. Measure the free play once you find it. If it is more than double the free play at the tightest spot, it is time for a new chain.
CLEANING AND LUBRICATION
This procedure is different for o-ring and non o-ring chains.
For a standard (no o-rings) chain you can clean it with just about any kind of solvent using a brush and a rag. Once you have it clean, lube it with a commercial chain lube designed for motorcycles. Read the label to make sure it is recommended for standard chains.
Take the bike for a ride and get the chain really hot. With the rear wheel supported squirt the lube into the inside run of the chain getting it into the side plates. If you lube the outside of the chain, centrifugal force just slings it off instead of forcing the lube into the chain internals. I find it easiest to put a slight bend in the can's straw and apply it where the chain runs over the bottom of the sprocket.
If you have an O-ring chain, you also want to make sure you use a recommended lube and follow the same lubing procedures for a standard chain. I clean o-ring chains after lubing them, not before. Just wipe off all visible lube on the chain and you're good to go.
DISCLAIMER: The methods in this article are guidelines, provided and performed by a trained mechanic. If you are not comfortable performing routine maintenance on your bike, it is recommended you get a trained mechanic to complete these and more difficult tasks on your bike.
BACK TO CURRENT COLUMNS
Chains and Sprockets: R & R
Switched Accessory Wiring
Drive Chain Clean, Lube & Adjust
Tool Guide for the Home Motorcycle Mechanic – Part 2
Tool Guide for the Home Motorcycle Mechanic – Part 1
Tire Inspection & Maintenance
The Cold Hard Facts about your Cooling System
Clutch Cable Free Play Adjustment
Hydraulic Brake System Maintenance
Belt Drive Adjustment & Care
Charging System Inspection
Chain inspection, adjustment and lubrication
Battery testing and maintenance
Checking your controls PT 1
Checking your controls PT 2
Tires and Wheels
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