How to understand Motorcycle Chains, Wear and Maintenance...
For most current motorcycles, the power from the engine and
transmission is delivered to the rear wheel via a drive
chain, although some models use driveshafts (many BMW's
and some Honda's come to mind), and others use belts
instead of chains (some Harleys, some Hondas, etc.).
While it can be argued that shafts are better because they
don't require nearly as much maintenance, shaft drives do have a penalty
in both total weight and (often more importantly) unsprung
weight. Similarly, it can be argued that belts are better
than chains, but the reality is that for an equal amount of
torque to be transmitted, a chain can be both much narrower
and generally be more reliable at transmitting that power.
Either way, your particular bike manufacturer made the
decision at the design stage as to which would be most
suitable to the purposes your bike is intended for, and in
most cases that means a chain.
TYPES OF MODERN CHAINS:
Motorcycle chains are broken down by a number of simple
criteria: width, length, and roller-support lubrication
design. Standard widths are 520 and 530. Standard lengths
are counted by the number of links in the chain --
110/112/114/116/118/120 are standard link counts, and you
can obtain chains up to 140 links from most manufacturers.
As for the roller-support lubrication method, that gets a
bit more complicated...
Cut away of a DID O-ring Chain:
NOTE: These are some of
many possible designs, and some sealed-ring designs place
the seal between the pin and the roller or between the pin
and the inner sideplate rather than between the inner and
outer sideplates. Furthermore, some do not have a roller-bearing
as a part of the support mechanism, but use a bushing or the pressure on the lubricant
itself as the roller support structure.
Old time chains were simply open-ended roller bearings and
you had to lubricate them exceedingly well to keep them
from wearing the bearings down too fast (usually by
immersing them in oil every several hundred miles). Newer
chains employ a sealed lubricant inside the chain roller
mechanism, and then maintain the seal on the lubricant
reserve using a rubber (usually a synthetic rubber-substitute
like NBR) sealing ring
of some sort. These chains are broken down by the shape of
the seal they use to seal in the lubricant. The typical
method is a sealant ring shaped like a big "O", and those
kinds of chains are called o-ring chains. Alternatively,
some manufacturers have designed sealant rings shaped like
an "X", a "W", a "Z" and a variety of other shapes to help
promote a long seal life (and avoid possible patent
infringement upon others).
Please note that simply because you
are using a sealed-link chain does not mean you do not need to lubricate it. Lube your chains!
Modern sealed-ring chains fail for only three primary reasons:
- Physical Interference:
Something sizeable gets trapped between the chain and the
sprocket after having been picked up, such as a wire coat
hanger. Other than picking a good path and trying to avoid
road debris, there isn't much you can do about this. Yank your clutch
in as fast as possible, kill the engine and coast to safe stopping place (if the
wheel is still turning -- otherwise try to keep it upright as you skid to a safe
place -- feet out!).
- Loss of Seal Integrity:
The seal(s) retaining the lubrication for one or more
rollers fails. Typical causes include: abrasion (such as
sand rubbing between the seal and one of the plates);
friction (heat generated by inadequate lubrication external
to the seals as the plates rub against them); weathering
and age (seal dries out, cracks), or other stresses (such as
chemical exposure to naphtha or other harsh chemicals). The
primary way to keep this kind of failure from occurring is
to keep the chain (and thus the seals) free of sand, dirt
and other contaminants via regular cleaning, and to keep it
lubricated appropriately externally as well (to minimize
the friction at the seal/plate interface, and to help keep
the seals in good shape).
Although it is also possible for the sealed lubricant to
leak out at another place (such as if the roller surface
detaches from the inner plate), this kind of failure is
- Roller-to-Roller Distance Elongation:
Sometimes called sideplate elongation,
which is usually technically be incorrect, depending on the
Over time, the repeated pulling on the
chain and overly tight chain adjustments causes the chain's subcomponents to physically
elongate, and the distance between any two roller surfaces
increases. Unfortunately, the distance between teeth on the
sprocket doesn't elongate the same way, and the result is
that only one roller is taking the majority of the force
from a sprocket at any given time, instead of sharing it
equally among the rollers in contact at that instant. This
causes the chain to elongate and to wear at an even higher
rate, and causes the sprocket teeth to start wearing
unevenly (forming a wave pattern). Over-tightening the chain tension
is usually part of the culprit. This form of failure is the most common
form of age/wear related failure, and can often be tied
into prior seal integrity failures.
To test for this kind of elongation, attempt to pull the
chain away from the rear sprocket at the back center. If
the chain can be lifted to the height of the top of the
sprocket teeth on any brand/model, then it is elongated enough to need
replacement as soon as feasible and is causing undue
wear. For most street-oriented motorcycles, replacement limit is around
1.5mm of play when measured like this (i.e. - being able to pull the
chain 1.5mm off the rear center of the rear sprocket).
Cutting Out Links from a Stretched Chain
Because of the roller-to-roller distance elongation issue listed above,
cutting links out of a chain that has stretched too long will do you no
good -- the chain will still wear just as fast, and the sprockets will
get worn down at the same accelerated rate as well. Just because the
chain is now physically shorter doesn't change the roller-to-roller
The picture on the right is an example of a chain that is failing at 7800 miles, although it has not reached it's
elongation limit by a far shot. Specifically, the chain has the following problems:
WHAT TO DO:
- The red color close to the seals on the exterior side-plates is the sealed bearing lubricant
normally used to lubricate the rollers. The seals are leaking, so the lubricant leaks out and dries
into a red powder (red coloring is common to most chain brands, but not all; it's the clay carrier
that is part of the lubricant package);
- If you look closely at the seals themselves, you'll notice what appears to be lengthwise grooves
in them; this is caused by using too hard a bristle during cleaning, one in which the material of the
bristles was harder than the materials in the seals;
- The inner side-plates are not aligned evenly, meaning that the lowest link in this picture is
already compromised beyond the point of failure;
- The rider said he diligently cleaned & lubed his chain every 400 to 600 miles. Based on what I see,
he should have cleaned less and lubed more.
- Replace this chain immediately! Failed seals cause chains to bind and break, putting the rider at risk.
- Lubricate far more often that you do -- remember, you can lube far more often than you need to clean!
- Change your cleaning method to a different method and/or use a softer brush.
- Seriously consider changing your lubrication -- use an oil instead of a wax. The fact that the rider was using
so much force to get the chain clean indicates that the lube product was clinging too much and not releasing debris & dirt.
MAINTENANCE - Sealed-ring Chains:
There are only four things you need to do regularly maintain a modern sealed-ring chain:
- Clean it of debris (sand, dirt, grime);
- Lubricate the exterior (oil or wax);
- Adjust it for elongation (not too tight!);
- Replace it when it's too elongated or worn, or the seals start to fail.
MINOR MAINTENANCE (every 100 to 200 miles):
MAINTENANCE (Minor + Major) - OLD STYLE OPEN-LINK CHAINS:
Open-Link chains require significantly more maintenance than sealed-ring chains:
MAJOR MAINTENANCE (every 600 to 1200 miles):
- Clean it of external debris (sand, dirt, grime);
- Lubricate the exterior (oil) and spray excess into the bearing links;
- Unmount the chain;
- Dip-clean it of internal debris (use a gallon container Kerosene or WD-40, plus a brush, dip repeatedly to wash any dirt, dust,
etc. out of the bearing area under each roller);
- Reoil the bearings (dipping it into a vat of gear oil or a pan of heated grease works well), filling all the bearings under each
roller with oil/grease;
- Remount the chain;
- Adjust it for elongation (not too tight!);
- Replace it when it's too elongated or worn, when any of the rollers are sloppy on their carrier bearings,
or when any of the roller bearings fail to turn freely even after dip-cleaning.
Most manufacturers recommend cleaning your chain thoroughly
every 500 to 600 miles (every 1000km) with kerosene (not gasoline, naphtha,
acetone or other petroleum products that dry out seals). Although old style
(non-sealed) chains really need to be physically soaked to
clean them, modern sealed-ring chains can normally be cleaned in
place unless they are totally trashed.
Moose Chain Scrubbers
The easiest method we have found to really clean an O-ring (sealed link) chain
well is the Moose Chain Scrubber (&
Sludge Away, a chemical which ships with it). The
device uses the chain's motion to turn the bristles,
scrubbing the chain as it passes through, and coating it
with a solvent that gets rinsed off with water afterwards. 90 seconds
from a gunked chain to sparkling clean.
One note: we do not recommend using your motor to turn the
chain when using this chain scrubber -- turn the wheel by hand
to pass the chain through, for safety reasons!
Your chain should be lubricated every time it is cleaned, and then
some. Generally, all chain oils and chain waxes work best if the chain
is physically warm (so the parts have expanded and the lubricant can penetrate
better). Remember that some seals may fail quickly; the lubricant you are
placing on there not only protects the seals, but also helps keep any rollers
with compromised seals working until the chain gets replaced. If in doubt about
what to use to clean your chain, follow the manufacturer's recommendation.
Although many people swear by standard WD-40
as their chain cleaning chemical of choice, I avoid it specifically when cleaning/lubing
any sealed-chains (O-ring/X-ring/W-ring) because of
the 45 to 50% Stoddard Solvent in WD-40 (stoddard solvent is commonly
considered dry cleaning solvent; I suspect it dries out the VOC's in the o-ring or x-ring
seals). WD-40 however, is perfectly suited to cleaning old-style open-link chains.
As for me, I personally spray down my chain with oil at the end of
every ten mile or longer ride, thus insuring that the chain
is constantly well lubricated and the seals are kept in
tip-top shape. Note that it is virtually physically impossible to
over-oil a chain (since excess oil will be flung off), but
it is possible to over-wax a chain. I'm planning on installing
a Pro-Oiler or a Lubetronic soon on my current ride, and have had Scott Oilers on past bikes.
Automatic Chain Oilers
If you ride long distances, or if you are not diligent
about lubricating your chain, you should take a serious look at
Scott Automatic Chain Oilers,
and Loobman Oiler (manual).
These devices place a single drop of oil (from
a reservoir) onto your chain every twenty to sixty seconds
while you are actively riding (NOTE: The Pro-Oiler is distance dependent instead of time-dependent, and the Loobman requires you squeeze
the bottle), and greatly extend the chain
life for a typical motorcycle by keeping the chain ideally
oiled all the time.
OIL OR WAX?
Note that both work, and each one has it's own benefits and
Wax tends to stick far firmer and longer than
oil products, reducing how often you need to lubricate the
chain, and providing a longer-lasting barrier against water. But
wax also tends to grab onto sand and dirt and hold it
really well, increasing the contamination level that can
lead to excess abrasion on seals.
Oil tends to lubricate better (greater penetration), and
doesn't hold onto sand & dirt contamination as well. But
oil also has a tendency to fling off more readily,
requiring more frequent applications. The upside to this
flinging is that as the oil flings off, it takes
contaminants with it, keeping the total contamination
So what should you use?
- If you live in an area that has lots of sand (coastal areas, deserts), use oil.
- If you are diligent about using a lubricant, use oil (keeps the contamination levels down).
- If you live somewhere that doesn't get a lot of contamination, use wax.
- If you are not diligent about using a lubricant, get an automatic oiler (Pro-Oiler,
Scott Automatic Chain Oilers,
and Loobman Oiler (manual)).
- If you're a starving college student, you can use automotive grease, used motor oil or vaseline in a pinch, and look at the Loobman Oiler.
Your chain should be checked for adjustment (slack) every time it is cleaned, and
anytime you suspect it may be too slack or too tight. The golden rule is
that slightly too loose a chain is infinitely safer (and
less like to wear prematurely) than slightly too tight a
chain. Chain adjustment methods vary between motorcycle
models, and we recommend you consult your owner's manual
for the proper amount of slack and the method to set the
chain tension adjustment by. If you don't have an owner's
manual for your motorcycle, we highly recommend you
obtain one -- try searching the net, or visit your local
dealership to order one. For most motorcycles that use a chain,
a total flex of 1" measured halfway between the front
and rear sprockets (1/2" up plus 1/2" down) is the ideal. Remember
that your chain needs to have some slack so that as it spins
up to full speed, it can have room for centrifugal force. The sample
adjustment below is for 1998 - 2003 Katanas, as per the owner's manual, as an
Your chain will need to be replaced whenever it becomes too
elongated, if the rollers are no longer turning freely,
and/or whenever your sprockets are starting to wear. It
should also be replaced any time you replace your sprockets
with new ones, and whenever you see red powder lubricant at the
links (see picture "Failure Analysis", above). A typical lifespan for a well maintained
chain should be between 8,000 and 15,000 miles (12,500 to
24,000 km). A typical lifespan for a neglected chain can be
under 5,000 miles and for an ignored chain is rarely over
2,500 miles. Chains using automated oilers often get 25,000 to 45,000
miles before they need to be replaced, making such oilers a good investment.
"Chain Tech - A Conversation with A Chain Legend"
by Yossef Schvetz, at Motorcycle.com.