Honda CG125 Servicing
The bike has been designed to be very easy to service,
there is no need to pay a mechanic.
If you insist on paying a mechanic, find out what their
hourly labour charge is, then insist on watching them work.
This means you will know they have carried out the work, the
real time it takes and how to do the work yourself next time.
The Owner's Manual states you should use a torque wrench,
there's no need for one unless your hands are very insensitive.
If you bought a 2nd hand bike,
the chances are the previous owners have not bothered to service the bike.
So I would advise doing everything in the Servicing pages
and this page
as soon as possible.
Servicing Pages
Oil
On this Page
Warranty
How to find your
bikes Tool Kit and Owners Manual
Manuals
Battery
Air Filter
Throttle cable
Ignition Timing
How to replace the Headlight Bulb
Storing the bike for months
Get bike working after
storing for months
Warranty
In the UK all new Honda CG125 come with a 2 year warrantee, it is
automatically transferred when its sold on to a new owner even if its 2nd, 3rd,
4th etc. hand.
In the UK the shop probably told you that if a Honda dealer does not
service the bike, the Honda 2 year warrantee is invalid,
this is a deliberate lie to increase their profits since
their servicing costs are often very, very expensive for hardly any work.
If you read the UK warranty book that comes with the bike, it
states anyone can service the bike and the warranty stays intact,
the only way to invalidate the warranty is if you do not
do the servicing correctly.
For instance if you forget to change the oil at the correct
mileage and the bike then develops a fault that is due to the lack of oil
change,
you can not claim on the warranty to fix that fault.
But if you have not changed the oil and the petrol tank
rusts through (very unlikely), you can make a warranty claim for a tank.
I have confirmed all this with the Honda UK helpline who
were emphatic about this.
I also remember the UK government passed a law about this a
few years ago,
to stop all motor vehicles begin forced to be serviced at
the manufacturers dealers, in order to keep the warranty.
Of course a dealer has no legal obligation to carry out
warranty work unless you bought it from them.
How to find your
bikes Tool Kit and Owners Manual
All motorbikes when new come with an Owner's Manual and a
basic tool kit for the bike.
These are normally stored in special compartments in the
bike.
Its not uncommon for the owner to remove and store the
Owner's Manual away from the bike, and do not return it when they sell the bike.
I would hope they do not do the same with the tool kit, it
should always be left in the bike when travelling in case of breakdown.
Trying to find these special compartments can be tricky
since they are small and often change from model to model of Honda CG125.
The tool kit for example is around 14 cm long, 7 cm wide and 3
cm high on the front disc brake model.
It has the very basics of tools needed for the bike, like
the rear suspension adjustment C spanner, spark plug tool and several other
spanners and screwdrivers.
On the front disc brake model, the special compartment is
behind the left hand side panel, beneath the battery.
But on other models it could be under the seat or even in
the tail of the bike or just strapped to the battery.
There's a small chance it could be behind the right hand
side panel, but all the space is normally taken up by the air filter.
How to remove the seat depends on the model.
It's usually held on by 2 screws or 2 nuts and bolts at only one
end of the seat (one on each side).
They are usually underneath the back of the seat pointing horizontally (look
underneath mudguard),
but some
models are at the front (need to remove both side panels to get to them).
There's even a possibility that instead of screws or bolts,
it has 2 latches at the back, pull them towards the back of the bike to release,
there could be a wire from the seat locked to the helmet
lock to stop people stealing the seat.
The other end of the seat is normally held in place by a
piece of the seat slotting in to a hole.
If there's a storage compartment in the tail of the bike,
you will need to remove the seat and unbolt and remove the grab rail,
unbolt the tail from the bike and remove.
The Owner's Manual is stored in a special compartment
beneath the right hand side panel on the front disc brake model,
but could also be in the same places as the tool kit
mentioned above in other models.
Manuals
My website has been designed so you do not need any
manuals, but if you have any of the following, I would use them as well as my
website
(always look at my website as well for any subject since it may or may not have
more information and be easier to understand).
You can buy the Haynes Honda CG125 Owners Workshop Manual,
this can probably replace the Honda CG125 Owner's Manual.
It also tells you how to service and repair the bike.
Make sure it supports your model year, you will also find
that it tells you everything about the oldest model it supports,
then in the back of the book it tells you the changes in
the instructions for newer models.
You can also buy the official Honda CG125 Workshop Manual
for your model of Honda CG125.
You can probably get it from your local Honda dealer,
but this manual is designed for experienced mechanics, so
it probably will not tell you how to do very universal basic things.
Battery
Its behind the left hand side panel, if not it must be
behind the right hand side panel (very unlikely).
If you have a maintenance free battery, you do not and must not try to check or
change the liquid levels below,
a maintenance free battery should have maintenance free printed on it.
The original battery in the front disc brake model is
maintenance free (all electric start Honda CG125 could be the same).
If you have a maintenance type battery (will not have
maintenance free printed on it),
you need to keep an eye on the liquid levels
of all 6 (6 V batteries only have 3) compartments.
Keep the liquid between the min and max mark.
You top the battery up with distilled water or deionised water
which is
available from most shops, including food supermarkets,
DIY shops, car shops, motorcycle shops and maybe even petrol stations.
You must only use distilled water or deionised water, do not use any other types
of water.
Distilled water or deionised water is also used in domestic steam irons and
other devices,
do not use it if anything is added to it (like perfume).
Never use battery acid unless it's a new battery just before or after it's first
charge.
Each compartment can be opened from the top of the battery.
For more information about batteries, faults and charging
see Electrical Faults in
the Basic Fault Finding page.
Air Filter
When to clean or replace the Air Filter has nothing to do
with mileage, it has to do with how clean the air is in your country.
You only need to replace the Air Filter if it has holes in
it or you can not clean it.
In the UK for example the air is so clean that you may
never or hardly ever need to clean the filter for the life of the engine.
In another country that for instants has a desert, you may have to clean the
filter every few miles in a sand storm.
You can always have a look at the Air Filter to see if it
needs cleaning or replacing (the cleaning instructions below will show you how).
But you can also simply check the spark plug or check it
when the engine runs rich (looses power and other things),
see Spark Plug in
Mechanical Faults in
Basic Fault Finding page.
The Owner's Manual tells you how to clean the Air Filter (if you do not
have it, see below).
The Air Filter is behind the right hand side cover of the bike (if not it
must be behind the left hand side cover, very unlikely).
Remove Air Filter.
If its paper type,
tap it and blow (in reverse so air
goes the opposite way through the filter) with a pump or compressor (front disc
brake model is paper type).
If its foam type, you can wash it.
Wash the foam filter in white spirit or warm water with detergent (washing up
liquid).
Make sure you rinse out all the white spirit or detergent thoroughly with loads
of water.
Make sure the foam is 100% dry (see below about squeezing) then soak in SAE 80 gear oil, SAE 90 gear oil or
SAE 30 (often sold for Lawn Mowers) engine oil.
Gently squeeze out excess oil (else exhaust will smoke until it's burned off).
Squeezing should be more like pressing, do not wring it out (do not turn one bit
one way and the other another) else you will damage the foam.
Throttle cable
If it stretches, adjust it to 2-6 mm free play,
the adjuster is on
the throttle cable,
there's a lock nut to undo first.
I was told by a Honda dealer that
the throttle cable is
maintenance free on the front disc brake model,
if it wears out you need to replace it,
you do not oil it.
I do not know if this applies to older models or not (see
Clutch Cable page for oiling).
Ignition Timing
All the 1995 ? (S & T models) onwards, Honda CG125 bikes have Electronic Ignition,
also known as Capacitor Discharge or CDI, it requires no maintenance.
The only reason to change the
Electronic Ignition Timing setting, is to bodge a worn out engine (if you are to lazy to
replace the worn out parts).
Some people change the Electronic Ignition Timing setting to try to get more
power out of the engine (not advised, its
not a sports bike engine).
If you have a Honda CG125 before
1995 ? (before S & T models) it could still have the old Points system, this requires maintenance
a bit like the Valve Clearance.
The Points system wears out (can
buy new points), is less reliable and does not work as well as Electronic Ignition (lack of power
at some engine revs).
If you have the Points system,
below are the details you need for the Honda CG125, you will need to search the
internet for a universal guide for Points.
You could instead look at the Haynes Honda CG125 workshop manual but its not
really needed.
The Points are behind the left
hand engine cover (gear lever side).
Follow steps 1 and 3 from the
Valve Clearance page, but instead of aligning up the T, align up F.
The points gap should be 0.3 mm (0.012
inch) to 0.4 mm (0.016 inch), 0.35 mm (0.014 inch) is were you should set it to
ideally.
How to
replace the Headlight Bulb
For information about different headlight bulbs, see
Headlight Bulb
in Accessories page.
The following is for the front disc brake model, I would
not be surprised if it was also correct for the front drum brake model.
The original bulb is a 12v 35/35w incandescent type with a
BA20d connection to the bulb holder.
Remove the 2 screws underneath the headlight (just behind
the chrome rim), they will be very tight.
Both screws will have a washer and a plastic tube that goes
through the hole, make sure you get both of them out as well.
Pull the bottom of the chrome rim away from the bike to
remove the headlight (this will be hard so use brute force).
When you remove the headlight, you will find the
headlight wire half way along has a connector, remove the connector (it has a
little clip).
The headlight should now be totally disconnected from the
bike.
Look at the rubber bulb holder, there's a small spring
connecting it to the headlight, remove the spring at that end.
Pull the rubber away at the edges, then lift the bulb
holder out, it has a little piece of metal sticking in to a slot in the
headlight at the opposite end to the spring.
You should now put a pair of clean gloves on, this is
critical if you are touching a Halogen bulb, its also recommended for any bulb.
I use normal disposable gloves that are totally clean, if
you touch the bulb without gloves you must clean it with a soft cloth and
mentholated spirit.
If you do not clean it, the bulb is likely to fail
(overheat and destroy itself) when you use it next due to the natural oil in
your fingers.
To remove the bulb, push it in to the bulb holder and twist
it anti clockwise.
To put a new bulb in, you will find it will only go in one
way round, the 2 bayonet arms are different sizes.
You may think a Halogen bulb has so much metal you would
not touch the glass / plastic sensitive part, but its impossible, you must wear
gloves.
Push the new bulb in to the bulb holder and twist
clockwise.
Find the little piece of metal sticking out of the bulb
holder (opposite side to the spring), put it in the slot in the headlamp.
Push the rubber back in to place to create a seal,
reconnect the spring to the headlight.
Reconnect the headlamp wire connector to the bike.
Put headlamp back in to bike and line up the screw holes
and put the 2 screws back in with the bits that were with it.
Storing the bike for months
You must get the petrol out of the carburettor or it can go off
and block the carburettor over a long time (often blocks the idle part of the
carburettor).
You can probably get the petrol out by switching the petrol
tap off and running the engine until it stops.
This is best done while riding the bike, the carburettor might
hold 0.3 miles of fuel (do not use 5th gear and pull clutch in when engine
stops).
Change the engine oil, see Oil page.
Oil the chain, see Chain
Oiling in Chain page.
Empty the petrol tank and spray inside with anti rust oil.
If you can not, make sure the petrol tank is full of petrol
to prevent rust.
Remove the spark plug and put a tablespoon of engine oil
down the hole.
Cover the spark plug hole with a cloth and turn the engine
over several times.
This is best done with the kickstart, if you only have
electric start its best to recharge the battery afterwards.
Then put the spark plug back in, see
Spark Plug page.
Remove the battery, you should also slow charge it every
month to stop it going off, see Battery section above.
Pump up the tyres regularly.
Take the weight off both tyres by putting blocks under the
bike, if you can not turn the wheels regularly.
Get bike working after storing for
months
Charge the battery and do not be surprised if you need a
new battery, check fluid level if its maintenance type, see
Battery section above.
Change the engine oil if it's been stored for more than 4
months, see Oil page.
Oil the chain, see Chain
Oiling in Chain page.
If the petrol tank was left empty with anti rust oil
sprayed in it, drain off the excess and fill with fresh petrol.
If tank was left with petrol in, it may have gone stale,
empty it or dilute it with fresh petrol if you have trouble.
If petrol tank was left with petrol inside it but not full,
expect rust inside tank,
it should fall to the bottom of the tank, the reserve
petrol tap position could pick up the rust and block carburettor.
If carburettor was left with petrol in the petrol could have gone
off and blocked the carburettor,
try fresh petrol.
If you still have a petrol related problem see
Petrol section in
Basic Fault Finding page.
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