Tires
Tires are a rather important part of the motorcycle and
should be inspected carefully.
Wear, of course, is the most noticeable and the tire will have a
wear bar (slightly higher rib across the tire that the wear is
measured from) Uneven wear and cupping of the tread will show
whether the tire has been ridden on improper air pressures. Also
check for cracks on the sidewall. These can be tricky to spot so
have good lighting or a flashlight so you can inspect the side
of the tire properly. If the tire is soft from sitting, you may
not see the cracks until you get the correct air pressure in the
tire.
Wheels
Wheels are not tires, they are what the tire sits on. There
are spoke wheels and cast (one piece or "mag" wheels) You want
to spin the wheel to check several things. Must be straight,
with no side to side run out. The up and down run out should not
be noticeable either. Don't mistake tire run out with wheel run
out. Grab the wheel and try to move it side to side. No movement
should be observed, if there is any, the wheel bearing may be
worn. Also apply the brake and release it and make sure the
wheel can spin as freely as before. If not then you may have a
brake problem.
Front Fender
The front fender should be there. It has to be mounted
securely and usually bolts to the lower fork slider. Check that
the mounting bolts are there and tight. Also check that the
bolts haven't been broken off. A good shop will check this for a
certification and getting those broken bolts out of the slider
can be a real pain. Make sure there are no cracks in the fender.
A lot of them are plastic. If you see a cracked fender or a bent
fork brace then the fork tubes may well be bent, telling you
that the bike has been down and not totally repaired. The bent
fork brace or missing fork brace is a sure bet giveaway that the
forks are bent so keep an eye out for that.
Brakes
You have to be careful when checking disc brakes. There is
the brake fluid to inspect. Pad wear must be addressed. The
condition of the rotor itself has to be looked at. Feel the edge
and if there is a ridge at the outer edge then they have worn.
If the lever comes into the bar when the brakes are applied then
it may be rotor time. The only way to really tell is with the
specs and a vernier. When looking at a potential purchase you
probably won't be able to check and measure everything so see if
the brake lever can be pulled into the handlebar. Check for
brake fluid leakage from the area of the master cylinder.
The pads can be inspected by looking at the caliper from the
front, looking up. A brake pad should be on either side of the
brake rotor. Sometimes there is a red wear line you can see.
Having a small flashlight will really help out here. There
should be pad material on the pad. If it has worn to metal then
the disc will have a rough finish and be burnt looking.
Brakes, master cylinder
The master cylinder is where the brake fluid is kept, usually
attached to the handlebar for front brakes and tucked away,
close to the rear brake pedal for the rear brake. The main
problem that occurs with these is the brake fluid itself. There
is a piston in the master that is activated by the lever that
you pull. If this piston is leaking then the brakes can be mushy
or there may be brake fluid leaking from the area around the
master cylinder. There is a very small hole in the master that
allows brake fluid to return back up to the master and if this
is blocked due to corrosion then the lever will be very hard but
no or little braking action will be taking place. If you
experience problems with a master cylinder then you may be
better off paying someone to look at this for you.
Brake Calipers
In the caliper a piston is activated by you when you pull the
front brake lever. It pushes against the actual brake pads to
apply pressure on the disc. One or several (depending on make)
"rubber" o-rings seal the fluid from escaping between the piston
and wall of the caliper. These rings serve another function and
that is to return the piston to its original position (brakes
off) These rings are the only thing returning this piston and
when there is corrosion, the piston can be forced on because the
hydraulic pressure is great enough to do so, however there is no
(hydraulic) help for the piston to return and thus causes the
brakes to be applied even though we are not pulling the lever.
The resulting application of the brakes causes a heat build up,
brake fluid expands (due to heat) thus forcing the brakes on
even more. This is not a good situation to be in as a
motorcyclist.
Brake Fluid
Master cylinders are where you will check the condition of
the brake fluid. They will have a little window to look through
or unscrew the top cover and have a look. It should be changed
every year but few riders do this. If it black or even dark
brown in color then it has to be changed. It should be almost
clear in color. This includes the fluid in the lines and
caliper.
Brake Lights
Brake lights are operated by a switch which is activated by
you pressing the pedal or pulling the lever. Usually it is not a
big deal to make these work if out of adjustment, if broken,
they are not too much money. The bulb is usually the culprit or
a misadjusted switch, sometimes even a loose wire. The way the
switch is located exposes it to the elements and they can get
corroded easily. A little lube every now and again will keep
them working longer.
Front Forks
The forks are a very important part of the bike as they
provide the front suspension of the vehicle. Having oil as the
damping agent means that there is an oil seal to keep it
contained. One per fork and if these start to leak the oil will
be all over your brakes and pants and not in the fork to help
dampen the load. This can cause handling problems as well as
ruin a set or two of brake pads. There is a tell tail ring of
oil around the fork tube so rock the (parked) bike a few times,
with the front brake on and then inspect the fork tube...any
oil???
The forks can also be bent and a slight bend is hard to spot.
Look at the forks from the side, line up both forks
visually...are they in line with one another? If not, they are
bent or twisted in the crowns meaning the front end has impacted
with something.
Also the forks may be damaged by pitting or rust and the
chrome coating may have started to lift meaning that the rubber
fork seal will get ripped every time that it passes the damaged
area. These can be expensive to purchase.
Steering Head
The steering head is what the whole front end assembly
swivels on. There are bearings hidden away in there that
sometimes need adjustment or replacement. You can tell if this
is the case by grabbing a handful of front brake and rocking the
bike forward and backward. If you can hear or feel any
play then adjustment or replacement is required. Also, elevate
the front end and turn the front end from full left lock to full
right lock. Is there any notching or grabbing in the movement?
If so...then it is time for new bearings and races.
Steering Stops
Steering stops are an important feature of motorcycles that
prevent the front forks from hitting the fuel tank at full lock.
When a motorcycle falls, the forks tend to jam up against the
stop and bend or break it off. If the handlebars come really
close to the tank or hit it then the steering stop has to be
re-welded or repaired to make it safe to operate. Because of the
different designs of steering stops there is no fixed price for
repair and varies depending who is doing the work. If the repair
is made by arc welding, the steering head bearings must be
regressed as the heat from welding will have melted away any
grease.
Handlebars
Older bikes have one piece handlebars, newer styles have two,
each one is slipped over the fork tube. The difference is style
and price. The older style bar is by far a lot cheaper to
replace than the newer style. They should not be bent. If they
are, then it tells you the bike has fallen. The throttle side is
the more important of the two because if it bends then the bend
can seize the throttle tube which spins on top of the bar.
You should not bend them back to shape...here's why. On the
first bend the outside of the actual bend (of the bar) is
stretched and weakened. Not good...but possibly still drivable.
If you bend it back then you now stretch the opposite side (of
the bend) and weaken it even more...possibly to the point it may
break while driving.
Throttle Grip
This is the twist grip that pulls the cable that increases
the fuel to the motor that makes the bike go faster. The main
thing to check here is that the throttle closes by itself. It
should snap shut. If it is hanging up then the problem must be
addressed to make the bike safe....and pass a certification.
Usually the cable needs a little lube or is routed incorrectly.
Light grease on the bar and inside of throttle tube will help as
well. If you purchase a set of grips, you will notice that the
inside holes are different sizes and this is because the
throttle tube is only on the right side of the bars....one grip
of the two is larger than the other and the larger of the two
goes on the right side (sitting on the bike).
Kill Switch
The "kill switch" or engine shut-off switch, as some people
prefer to call it, is an added safety feature that enables you
to shut off the motor without removing your hand from the
handlebars. It should move to it's off or on position with a bit
of a "click" If it feels mushy or loose then it may well be on
it's way out. If it breaks inside, then the motor will stop
working and it can be hard to track down the problem.
Remember....look first for the items that get used the
most....they will break first.
Handlebar Controls
No one pays much attention to these components and hey...what
to keep adjusted...nothing. Just make sure they function and are
not ready to fall off. If one of those itty bitty levers for the
signals or high beam, for example, falls off ...you have to buy
the whole assembly to the tune of nearly $100.00 each side if
you live in Canada (some models are more). If the bike you are
looking at is missing those, don't get sucked in by the old
"...oh, how much could that little thing cost"
Levers
Levers pull the cables that operate various systems of the
motorcycle. If the ends are scuffed then you know that it has
impacted something, probably lightly as they are the first to go
in any fall. Good idea to have some spares on any long tour you
may make. They should have some free play and not be bent. They
usually snap if you try to straighten them.
Cables
When you pull the lever the cable should have a smooth action
and return to its original position sharply. There should be
free play at the control end of the cable. You shouldn't be able
to see any broken strands of wire. You should see some sign that
the owner has lubed it.
Cable Routing
The perfect routing for a cable would be a straight line.
That is not possible on a motorcycle so as straight as you are
able to make them is the rule. When inspecting the bike, turn
the bars from side to side and make sure that the cables don't
get pinched by the forks or pulled too tight at full lock. If a
throttle cable gets pulled on when the bars are turned a certain
way then you are an accident waiting to happen. Factory service
manuals usually have several pages devoted to cable routing.
Certain models of bikes may have different needs in terms of
where the cable has to go to function correctly.
Sprockets
Sprockets are what the chain rides on to transfer the
horsepower from the motor to the rear wheel. They have a given
number of teeth which the chain engages with. You must look
sideways at the sprocket and see if the teeth are hooked at all.
They should be flat at the end...if they are sharp, then the
sprocket is worn. The higher the horsepower of the bike then the
faster the sprockets wear. If the sprocket is replaced then the
chain should be replaced as well. Spinning the rear wheel
backwards (elevated and by hand) you will hear the chain
grabbing if there is any hooking.
Chain
When you inspect that potential purchase for chain wear you
can look to see how far back the wheel has been adjusted to. If
the adjusters are screwed in all the way, then it's a sure sign
that the chain is totally worn. If the chain pulls back from the
back of the rear sprocket then it worn.
Shaft Systems
The shaft drive system is almost maintenance free. At the
rear axle you will see that oil goes in the rear housing. There
is a large bolt in the top which, when removed, is where you
pour in the oil. A smaller bolt on the side about half way up
the housing is the level check. If you remove it then the oil
should be at that level. There is another bolt at the bottom and
that is the drain bolt. The oil used is a mineral based oil,
Hypoid, and it has a unique odor to it. Don't use ordinary oil.
You shouldn't have to worry about anything in this setup because
it is rather bulletproof.
Shocks
The front suspension we have covered and the same theory
applies to the rear suspension. There are two types...Dual
shocks and Mono-shock...
Mono-shocks are not as easy to spot because they are tucked
away in the guts of the bike. Look in front of the rear wheel
and there should be a tube like cylinder running up to just
under the front of the seat. It may be shrouded and all you can
do would be to look for oil leakage in the area. The best test
is to bounce the suspension and see how it reacts.
Dual shock types of suspension are totally visible and there
will be one on each side of the bike, attaching the rear of the
swingarm to the rear area of the frame, usually near the back of
the seat. They should be straight, no oil leakage is supposed to
be there. Once again the best test is to bounce the suspension
and see how it reacts. (I will add to this in the near future :)
Swingarm
The swingarm holds the rear wheel and pivots up and down to
allow for suspension travel. There is not much to go wrong with
a swingarm except the side to side play it may develop. With the
bike on the center-stand (or elevated) grab the swingarm and
apply side to side force. If side to side play is found then you
would have to tighten the swingarm nut. If it is already at the
required torque then the swingarm bearing or bushings need to be
replaced. This kind of job you may wish to pay a service shop to
do for you.