This information was kindly donated by http://www.BIKEPOINT.COM.AU
INTRODUCTION
It's a grubby job and it has to be done adjusting and lubricating the chain that is. The good news is that it shouldn't take more than 15 minutes once you have a handle on exactly what to do.
How you go about it will depend on the type of bike you own. Some use snail cam adjusters at the rear (so named because of their shape), others eccentrics (because of how they run in the swingarm), then there's the plain old screw adjuster in the end of the swingarm and finally you'll come across some single-sided variations on bikes such as VFR Hondas, T955 Triumphs and Ducati 916s.
In any case, the general principle remains the same: you want to take the excess slack out of the chain, without overdoing it, and make sure the back wheel remains more or less straight in the process. You also want to keep the chain lightly oiled, again without drowning it.
A tight chain will place a lot of unnecessary strain on itself, the sprockets and even gearbox bearings. Keep running chains too tight and you can do a lot of expensive damage. In fact, you're better off having the chain running a little loose rather than a little tight.
Have it too loose, however, and you risk the chain thrashing around and causing increased sprocket wear or, in a worst case, throwing itself off the sprockets altogether. If the last happens while you're riding, you are almost guaranteed to crash as it tangles with and locks the back.
A well adjusted and lubricated chain is, however, a wonderful thing. It transmits the power smoothly (you can actually see the difference on a dyno), lengthens the service life, smooths out your gear changes and makes the bike feel better to ride
MYTH BLOWING
Let's blow one myth out of the water. It's the one about a bike with a centrestand is always much easier to adjust the chain on than one without. What a load of twaddle.
You should in fact check the chain tension with the bike on its wheels thus making the centrestand redundant and preferably with someone sitting on it. The idea is that you want the chain at maximum extension or with the front sprocket, swingarm and rear sprocket all in line with each other.
That is when the chain is at maximum extension. On most bikes, the distance between the front and rear sprocket varies significantly as the rear wheel swings through its normal extension arc.
In the real world, you may not have the means to get it all lined up perfectly, but plonking yourself in the saddle (with the bike off the centrestand, remember) and using your own weight (or that of a friend) is a good start. Wiggle the lower run of the chain as close as possible to the middle. You should have about 15-20mm of slack up and down.
Less and it's probably too tight; more and it's too loose. Roll the bike forward, say 60cm, and check again. Do this a couple of times. What you're checking for is tight spots, which will happen occasionally, and you will have to adjust where the chain is tightest.
HOW?
See your owners manual is the short version it will tell you exactly how to loosen the rear axle on your bike and move it for adjustment.
In general, the only bolts you should have to touch are the rear axle in some cases or the bolts holding the axle clamps, plus the adjuster bolts themselves (if there are any). On bikes like the late-model VFRs with Pro-arm, you loosen a clamp and use a C-spanner to make the adjustment.
Older series Hinckley Triumphs, for example, use an eccentric in a double-sided swingarm, where you loosen two clamps at the end of the swingarm and roll the axle to the desired position with an oversized Allen key.
Current Blackbirds, as another example, are more conventional, requiring you to loosen the axle and then turn a couple of adjuster screws. This system is also the most common on older machinery.
None of the systems in current use are complex but it is critical that you have good tools. Forget the bike's toolkit, as in 99 percent of cases it borders on being junk at worst or barely adequate at best. Work out what size spanners you need and buy some good ones. The savings in skinned knuckles and stripped bolts will easily justify the cost.
Okay, so we've checked the tension it's too loose and we now have the relevant axles/clamps loosened. The idea is that you move the rear wheel back gradually a millimetre or two at a time and reckeck the tension. A small amount of rear wheel movement will make a big difference to the taughtness of the chain.
Hopefully you'll be able to leave everything loose, sit on the bike (or get a friend to do it) and check the tension. Some bikes running eccentrics may not allow this you might have to nip up the clamps quickly while you double-check.
If you don't like the idea of doing it on the wheels, you can take an educated guess (usually leaving a little extra slack) and do it on the centrestand. But you need to check it isn't too tight on the wheels once you're done.
On most bikes, you are also aiming to move both sides evenly. The swingarm will have markings near the axle to act as a guide and the general idea is to keep them even. That is, if it's back four notches plus a mil on one side, make sure it is on the other.
Strictly speaking, you should take the opportunity to do a wheel alignment which ensures the rear wheel is running straight. This takes on greater importance if you're using the bike hard at the track or wherever, but is less critical for normal road use. We'll cover that another issue.
DOUBLE CHECK
Once you have the tension and perhaps the alignment right, you need to nip up all the bolts again. Most people will not have a tension wrench, though it can be handy. Axle bolts and axle clamps generally require a lot of force the amount required to undo them is often a guide.
However adjuster screws and the like need to be treated more gently. If you're unsure, get someone with a little more experience to show you.
What is critical is that you double-check that everything you touched is back where it should be. Riding off on a motorcycle with a loose rear wheel (it happens) is a hair-raising experience.
LUBE
The ideal environment for a chain is one that's free of dirt with a constant and minuscule supply of oil the direct opposite of what they experience. Most bikes run O-ring chains these days, which means the links have lubrication trapped inside the link behind O-rings. That lengthens the life considerably, though they need some help.
Even an O-ring appreciates some external lube to cut down the friction on the sprocket and therefore keep the running temperature down.
There's all sorts of theories are getting around on lubes. The ideal, if you believe the chain manufacturers, is something like an occasional wipe with 90 weight gearbox oil. The catch is that it should be done every couple of hundred kilometres.
For most the practical option is spray lube. Generally you should apply it while the chain is warm (just after a ride) and allow ten minutes of so for the carrier liquids to evaporate.
You apply it to the inside of the chain (spray it on top of the lower run, forward of the rear sprocket) and remember a little goes a long way. Using a tiny bit frequently is the best way to go.
The only catch with a lot of commercial sprays is that they are sticky (so they cling to the chain) and therefore pick up dirt along the way.
The ideal lube is a constant one. Some bikes over the years have had a drip feed to the chain, while others have successfully used fully-enclosed drive systems. The best alternative around at the moment is an automatic oiling gizmo, like the one made by Scottoiler (www.scottoiler.co.uk). I've owned a few of them on different models (including the current Blackbird) and like their ability to supply an adjustable oil feed to the chain whenever the bike is running. See elsewhere this issue for more details.
Regardless of what you're using, it pays to clean the chain occasionally.
All you need to do is get a rag soaked in kerosene (not petrol, which will damage the O-rings and dilute the lubricant inside) and wipe the chain. Do not, under any circumstances, be tempted to prop the bike on the centrestand, start the engine, put it in gear, and then let the chain run through the rag. There are gruesome cases of people watching the rag get caught in the chain, and then their hand, with inevitable results.
HOW OFTEN?
How often should you adjust and lube the chain? That depends entirely on your riding. Hard riding, unsealed roads and wet roads all punish a chain. So does a lot of horsepower and a heavy bike.
Only familiarity will answer that question, but a weekly check is a good place to start if you ride most days.
On longer runs, take a can of spray with you you can get them in mini sizes and apply it at the end of the day.
Looked after, a chain and sprocket set should do 20,000km and anything up to double that. The signs that replacement is due include sprocket teeth that have gone from large rounded teeth to something sharp and shaped like out of a shark-catching doco, or the simple give-away that you're reached the end of the adjustment.
Like a lot of things in life, looking after a chain is easy with a little care and practice.
Guy Allen