Motorcycle Drive Chains
Cleaning and adjusting of the
motorcycles drive chain is one of the most neglected maintenance requirements
of any motorcycle. It's a time consuming, dirty task to clean, lube and adjust
the chain.
Chain drive is used on more motorcycles than drive shafts
and belts. The drive system of chain and two sprockets is lightweight,
efficient, and allows for easy gearing changes.
However what few
riders understand is that they still need to be maintained and adjusted.
Today's chains are made of stronger materials but are still subjected to the
some conditions, stress from horsepower, weather, and the rider's lack of
attention to shorten their life spans.
Drive chains are made up of links, side plates,
pins and rollers. It's the rollers which engage the sprockets teeth. The
chain's ends are joined together by a master link. The master link may be
staked, which is the strongest and safest method, creating an endless chain; or
by use of a spring clip. The staked master link requires special tools to
install or remove it. The spring clip 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.
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 of the o-rings.
Those little
rubber rings have solved one of the chain maker's biggest headaches for many
years: 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, it throws away the oil. The only reason for chain wear is the loss of
lubricant. The advent of the O-ring chain helped the chain to keep its oil
inside and stay lubricated were 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.
Even the
cheapest chain without O-rings will last a surprising amount of 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
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 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 ideally 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 a 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 and unnecessary tensile loads can
exceed the chain's capacity and the increased friction will raise the chain's
temperature quickly.
A new chain, adjusted to tightly will in no time
at all, turn into history. 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 owners manual will have the recommended method and amount of
free play in the chain. Use the either method.
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. Also the sprockets will suffer. 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 cockeyed, sideways 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
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 tensioner 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. Even after all this straightening,
it's worth checking that the chain runs even, 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 can cure this.
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, totaling chains in no time.
the relieved teeth sprockets available in the aftermarket help a great deal in
reducing chain wear and stretch by letting the dirt out of the high-pressure
area. Proper maintenance of a dirt bike's chain also means a good hosing after
the ride, first drying (watch your fingers!) and only then, oiling. By the time
of the next ride all excess oil will have dripped away, reducing dust pick up
to minimum.
Chains really don't strectch; as they do their job, the
lubericant between the pins and bushings is burned off by heat and friction,
loose enough of it and rapid chain wear takes place. As various pieces grind
away at each other, play developes between the pins and rollers. With the extra
play, the chain elongates.
Sprockets, as a rule do not requrire any
maintenance other than inspecting the mounting bolts and cleaning. As the chain
wears and strectches, or the chain is allowed too mcuh slack, it will ride up
on the sprocket teeth. This will quickly wear the teeth into sharp hooks.
Inspecting 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.
530 EK heavy duty o-ring chain
Manufacturers use numers a series of numbers:
420,428, 520, 530, and 630, followed by a series of letters ot designate type
style and strength. With motorcycle drive chains the first number will always
be a 4, a 5, or a 6; these numbers correspond to the chains size or physical
dimensions.
Chanins 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 eithths. A 4 series chain measures 4/8 (1/2) inch between pins. A 5
series chain is 5/8 inch between rollors and a 6 is 6/8 (3/4) inch.
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 measuremets, 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 makers 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. Rememeber a chain is only as strong as it's
weakest link. Using the inccorect master link; a 5,000 lb in a 10,000 lb
aplication can drive that old adage home. Never mix chain pieces or
manufacturers.
Always check your owners or service manual for
recommended types of chain or the chain manufacter'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 possibley streach faster letting
the chain saw away on parts of you motorcycle, or worse break leaving you a a
long walk home.
Ok your 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,
but WD 40 works well and its easier to handle and far more convieent 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.
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. The chain and sprockets are 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 on your chain lube on the inside
of the chain, (That's the part of the chain that wraps over the sprockets yes
the inside. Centrifical force will push the lube into the chain as you ride).
Let it stand for a few minutes, read the lable on the can for the time it will
take for it to work it's 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, 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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