Honda CG125 Brakes
Rear Brake
Free play (slack, before brake works) from the brake pedal to the ground should
be 20 to 30mm (use a ruler).
You can adjust the Free play with the nut on the brake rod on
the back wheel.
Check the brake light comes on afterwards when
rear brake is applied, if it does not see
adjustment
wire in
Light Bulbs section in
Basic Fault Finding page.
There's probably a brake wear indicator (if not see
How to
remove and install the wheels in the Bike in the Tyres
page to find out how to remove the rear brake),
press the brake pedal down and look at the top of the arm
that moves on the back wheel as you press the brake pedal,
look for a small arrow on the arm (may need to be cleaned)
and watch it move towards the mark (a piece of metal sticking out) on the drum
as the brake is applied.
If the arrow hits the mark when the brake is fully on, the
brake shoes need to be replaced.
Replacing the brake shoes is pretty easy see
How to
remove and install the wheels in the Bike in the Tyres
page to find out how to remove the rear brake.
I recommend the EBC brand of brake shoes, you should find most motorcycle shops
sell them or can order them (especially in the UK).
Front Drum Brake
It should have 20 to 30mm of free play (slack, before brake
works) between the lever tip and the handle bar, you can adjust it with the nut
on the brake lever.
See
Clutch cable page to find out how to adjust the nut.
There should be a brake wear indicator like on the rear brake, see
Rear Brake section above for more details.
The front drum brake can lose braking performance due to increasing resistance.
The cable may needing oiling (see
Clutch cable page) or if really bad needs to be replaced.
The pin on the brake may corrode (depends on time and weather) and increase resistance substantially (I can
not advise on how to sort it yourself).
Of course the brake shoes (brake material) also varies in quality and
performance.
I recommend the EBC brand of brake shoes, you should find most motorcycle shops
sell them or can order them (especially in the UK).
Sometimes a leaking fork seal can drip oil which may get in to the brake drum. If this gets on to the brake friction material, the results will be bad.
How to improve the Front Disc Brake
How and when to change the Brake Pads
Front Disc Brake fluid level
Front Disc Brake fluid changing
How to
improve the Front Disc Brake
The original pads are Nissin Sintered NKX16FF and I think they perform
terribly (I think they are unsafe), I have explained in more detail later on in
this section.
You can tell if you have Nissin pads by looking through the front wheel,
Picture 1
Picture 2 of Nissin pads.
As a result I have replaced the Nissin pads with EBC SFA54 Organic pads.
They are completely the opposite of the Nissin pads, they have more stopping
power than I can use (I have tried emergency stops).
They have feel, progressiveness, smoothness, quiet, as well as not needing a lot
of pressure to use them.
After running the pads in and using a braided brake hose, I can stop with
one finger, stop quickly with 2 fingers and very heavy braking needs 4 fingers.
I very highly recommend them (for your safety and enjoyment),
I have been told and read from several sources that EBC make the best Organic
pads and my results have been so good I believe them,
I have used other brands of organic pads in other bikes and none of them were
anywhere near the performance of the EBC organic pads.
A friend of mine has put the EBC Organic pads in his Honda CG125 and found
they still work brilliantly,
even with a passenger on the back and down a steep hill (25 stone combined
weight).
He also found they work brilliantly when its heavily raining and the roads are
soaking wet (they work immediately, no delay).
I have tried the EBC FA054HH Sintered pads. They require more pressure
from your fingers compared to the EBC SFA54 organic pads.
Because the Honda CG125 has a poor quality / low power braking system, I did not have enough pressure to
brake as well as the EBC Organics.
Even though I had fitted a braided brake hose, so I highly recommend you use the EBC
SFA54 Organic pads instead in the Honda CG125.
In other makes and models of bike the EBC Sintered pads may or may not be better than EBC Organic.
One mistake I did make when originally fitting the EBC SFA54 Organic pads was
to transfer the metal shim from the Nissin pads Picture
The brake piston pushes against the metal shim, as you can see from the
Picture it means the piston does not push
evenly over the pad.
This resulted in the pad wearing unevenly, increasing brake binding and noise
while decreasing power and feel.
Luckily I realised my mistake quickly and removed the metal shim.
If you want more information about the Nissin pads and why I think they are
so unsafe and a possible fix to make them safe, I will try to explain.
The Nissin pads do not seem to have much friction so do not slow the bike
down much or well.
I have tried a braided brake hose which increased braking pressure.
Cleaned the disc with brake cleaner.
Brake calliper was stripped down / cleaned and all new rubber seals put in.
Brake fluid changed.
I tried a 2nd new identical set of Nissin pads (they were 4 years younger than
the first set).
All this made no difference to the Nissin pads performance.
The only way to get the Nissin pads to work
is to heat them up by braking a lot before you actually need them.
My biggest concern is when you need to brake heavily or in an emergency I found
the pads friction disappears (feels like the disc is as slippery as ice).
Its simple for you to see if you have the same problem, try braking hard (not
massively) and see what happens, of course leave lots of room to prevent
accident.
Down hill, back wind or when carrying some weight will make the problem far
worse as well as how fast you are going.
But the following information seems to fix all of the problems (but the EBC
brake pads are still miles better),
I am not sure why but it could be it puts grit on the pads to create friction or
it corrodes up the brake so the pads are binding all the time (so generates
heat).
The only thing I found to get the Nissin pads to work was,
in winter the roads had
salt on and were soaking wet.
The brake hardly worked at all, with water and salt all
over it,
so I had to put far more brake pressure on than normal and
it took a very long distance to stop,
after a very few miles of this the brake doubled in power ever since.
I don't know if it was the salt water or excessive braking
that did it.
The excessive braking over a long time can only be done with the disc constantly
being soaked with wet roads and rain so it takes a long time to stop.
How and when to change
the Brake
Pads
I very highly recommend the EBC SFA54 Organic brake pads, see How to improve the Front
Disc Brake section above.
Other Manufacturers part numbers are GOLDfren
144, Dunlopad DP107, Ferodo FDB250, SBS 536, Vesrah VD120.
The part numbers do not include the pad material type or what they are designed
for, you want one designed for road or race use, not off road.
The pads should have a worn out indicator, but if you can
not see it, the pads are worn out when there is very little brake pad material
left (around 1mm).
Use a torch to see both brake pads (one pad on each side of the disc), often the
hard to see pad can wear down faster than the other one.
If you ever hear or feel what seems like metal grinding
against metal, your pads are worn out and must be changed immediately or you
will damage the disc.
When the brake pads wear out, changing them is very simple and quick if the
brake is not corroded inside (heavy corrosion will make brake bind excessively).
If you have a corrosion problem inside, I highly recommend you get it sorted as soon as
possible.
If you let it get to bad, you could end up having to buy a new calliper and they
cost around £150.
If the brake is corroded inside my recommendation is to see a mechanic (to difficult
for a beginner).
Actually my recommendation is to get a mechanic to change the pads for you
regardless of if its corroded or not (if price is right, see below).
I have explained most of the important things in the sections below to help you
or a mechanic.
A good mechanic should only charge around £10 to change the pads for you if
the brake is not corroded (£15 is to much, £8 is more common).
Of course you always get mechanics and shops that want to charge dramatically
more than this, so shop around until you find a good one.
You must watch them working on your bike, if they will not let you, walk away
and find another mechanic or shop that will.
Time how long they take to do the work and find out how much they charge per
hour before they start work.
This will make sure they actually do the work and they do not claim they worked
for much longer than they actually did.
To change the pads, you should not need to mess around with the brake fluid reservoir on the
handlebars unless its been over filled (just in case put cloth around it).
What can happen is if its over full, when the brake piston is pushed back (when
installing new pads), the fluid is pushed back in to the reservoir and could
overspill.
To remove the brake pads all you have to do is remove the 2 pad pins
Picture (as long as the brake disc is not
between them).
The brake pad pins could be so tight you may have to
remove the
front wheel to get enough leverage on them and or use a longer 5 mm
Allen key.
Do not transfer the metal shim if fitted to the old pads, there is a paragraph
about it in the How to
improve the Front Disc Brake section above.
You have to push the brake piston back since new pads will be thicker
(see internet for information, you may want to clean the part of the piston that
is exposed).
The brake piston should push back easily with just your two thumbs, if it will
not you have a corrosion problem, probably behind the piston seals (see below).
The brake piston can not be pushed back at an angle, it has to be pushed back
evenly on both sides (one thumb on the left, the other on the right side).
You should clean the brake disc with some brake cleaner before fitting new
pads (to stop them being contaminated).
The brake pad pins will also probably be corroded so need to be cleaned (sand
paper / emery paper) and a very thin layer of copper grease put on (to protect).
There is a metal plate that acts like a spring for the pads, this may have
become corroded and needs to be removed and cleaned
Picture
If you remove the brake from the bike (from the fork), do not over tighten the 2
bolts when you put it back on the fork (remember how easy it was to un tighten)
If things have gone wrong due to corrosion, when everything is back together
you may have an excessively binding brake.
I would not ride the bike like it, I would get a mechanic to fix it.
Ask the mechanic to check both floating Calliper Pins (6 mm, behind rubber bungs
on outside of calliper) first
and see if it fixes the
fault,
one pin, probably the top one could be corroded and the other ok (bottom pin has
a O ring seal, top pin does not and calliper will not let you fit a O ring).
The calliper pins / rubber parts are meant to have silicone grease on them but
some people use / prefer to us a small amount of copper grease instead.
If that fails to fix the fault, it must be the brake piston seals.
You have to remove the brake piston which will result in loosing all the brake
fluid.
The bad brake design
means its very hard to get brake fluid back in without a vacuum bleeder.
I did not have a vacuum bleeder so had to bleed the brake pipe between my
fingers (with gloves on),
then push it in to calliper before reservoir ran out of brake fluid (not
easy).
Only then did I have enough brake pressure in the system to bleed the rest of
the air out the air bleed screw hole (that's not normal, its a bad brake
design).
If the mechanic has to clean or replace the brake piston seals / clean the
metal behind them, all the brake fluid will be lost from the system,
this is the perfect time to replace the original rubber brake hose with a
braided hose.
Rubber hoses only last a few years, braided hoses last forever. A braided hose
gives you more power (pressure) and feel of the brake.
The easiest way to remove the brake piston is when the brake pads are
removed,
put a little pressure with your fingers on the brake piston (pushing it back in
to the calliper),
while operating the brake lever fully many, many times (the piston will move out
very slightly every time the lever is pulled in).
You will have to top up the brake fluid reservoir from time to time else you
will run out of fluid to pump.
Like all brake pistons, it is very delicate and should not be pulled out of
the calliper (unless you can with your fingers).
The method in the section above will push the piston out of the calliper without
needing to be pulled.
If you damage the brake piston you could easily end up with a brake fluid leak
(brake will not work and new piston is around £30).
If you damage the brake calliper metal behind the seals you can also easily have
a fluid leak (brake will not work and new calliper is around £150).
Since both are very delicate, unless you are sensitive or skilled, it could be
better and cheaper to get a mechanic to work on them.
You may be able to temporarily bodge a piston seal problem by cleaning the
seals with brake fluid when the piston is out.
But the main corrosion problem is likely to be the metal behind the seals
needing to be cleaned.
The brake piston has 2 seals. The one nearest the outside is the dust seal,
this is meant to have some silicone grease put on it.
The other seal and the piston it self is meant to be coated in brake fluid.
When the brake piston is out, you can easily unscrew the brake cable from the
calliper, then take the calliper to a mechanic.
Then let the mechanic do all the delicate / sensitive work.
Without the bike, the mechanic will probably not be able to remove the calliper
pins unless you have slackened them off on the bike.
The calliper pins are often so tight, you will probably need an extra long 6 mm
Allen key (may need a tap from a hammer).
The mechanic may struggle or not be able to remove the brake pad pins unless you
slackened them off on the bike as well.
See How to improve the Front Disc Brake section above for my recommendations on what Brake Pads to use and not use.
Check the fluid level in the sight glass on the side of the
reservoir (next to the brake lever).
Move the handle bars from fully left to right to see the
fluid appear and disappear.
When the handle bars are straight see how far up the sight
glass the fluid reaches,
note the Lower mark near the bottom right of the sight
glass, never let the fluid level drop below this mark.
As the brake pads wear down the fluid level will drop.
Front Disc
Brake fluid changing
I advise you to change the fluid if it's a new bike before
the 2 year schedule,
I changed it 2 months early and noticed a substantial
improvement in power and feel.
There are several different ways to change the fluid,
you can buy a one way valve brake bleeding system for less
than £10 and instructions are included.
Its pretty easy and I recommend you try it, just remember
brake fluid eats paint so cover it up.
The smallest bottle (250ml) of DOT 3 or 4 brake fluid is needed.
Brake fluid goes stale over time once the bottle has been opened so do not buy a
larger bottle than required.
A 250ml bottle has far more brake fluid than you need anyway.
Any brake bleeding device will come with plastic tubing to
connect to the brake, if you do not buy anything,
you will need transparent clear plastic tubing with an internal diameter of 5mm,
available from car shops and maybe DIY and fish tank
shops.
The instructions below are how I replaced the brake fluid,
it's a combination of the one way valve system and the non one way valve system.
The instructions might make it look hard and complicated,
but it really is very easy, lots of the instructions are not needed,
there just in case something goes wrong (unlikely).
I used the metal one way valve (look for the arrow on it,
for the direction of flow) with transparent clear plastic tubing on each end
(small tube = brake end).
The plastic tubing was very determined to stay in its
coiled up state, you need someone to help you keep it straight,
or you could trap it (I put it through a large funnel which
I trapped in the handle of a large bucket).
1. Remove the small black rubber cap (see picture above) on the brake bleed
nipple (disc end of brake) and attach the small tube.
2. Unscrew and remove the brake fluid reservoir lid (on the handlebars),
there's a second lid inside that you need to pull out.
3. Pull the brake lever in slowly (as far as you can
without excessive force) and slowly release, repeat this 3 or 4 times to get the
pressure up,
then pull it in again slowly and hold
while very slowly opening the brake bleed nipple nut (the pressure on the brake
lever will reduce,
keep pressure on lever, when lever hits
handle bars, keep it there), as soon as fluid flows easily in to the transparent
pipe, stop opening the nut.
When the fluid stops moving, close the
nut and only then release the brake lever slowly.
4. Repeat step 3 until brake fluid has gone through the one
way valve.
5. You can now leave the nut open and slowly pull the brake
lever in and slowly release over and over until nearly all the fluid is out of
the reservoir,
do not let air get in to the small pipes
in the bottom of the reservoir or you will get air in to the system.
6. Make sure you have covered everything around the
reservoir since you may spill the brake fluid, which eats paint, even a single
drop.
Pour new brake fluid in to the reservoir
(must be an unopened bottle, it goes off as soon as it's opened).
Keep repeating step 5 and put new brake
fluid in when needed, when the colour of the fluid in the transparent tube
changes,
you have replaced all the old fluid in
the brake system, if you do not notice the colour change,
you must have changed all the fluid when
most of the small bottle is used.
7. If the brake lever looses all or some of its pressure,
you have let air in to the system, repeat step 3 to get it out.
8. The fluid in the transparent tubing before the one way
valve should not have any bubbles or foaming in it, if it does you need to get
them out,
you can try step 3 again, you may also
need to experiment with the bleed nut (try opening it less or more),
you may also have to try closing the
brake bleed nut before the brake lever touches the handle bars.
9. When finished, make sure brake bleed nut is closed tight
and top up the reservoir (never let it drop below the Lower mark).
10. Put reservoir lid back on and then the outside lid, you
do not need to tighten screws very hard since its all rubber,
remember how easy it was to
unscrew.
11. Any brake fluid that has been spilt needs to be diluted
with loads of water to stop it eating things,
it's normal for some brake
fluid to have escaped around the brake bleed nut.
12. If you have trapped air in the brake system (unlikely),
the brake will have a lack of pressure and feel spongy.
If step 8 does not fix this
problem, the air is trapped higher up the system, you need to make sure the
brake bleed nut is closed tight,
then slowly pull the brake
lever in until it touches the handle bar, then tie the lever to the handle bar
while it's still touching, leave it like that overnight.
Then open the bleed nut
slowly and hopefully the air will come out. If this still does not totally work,
try again, the reservoir lid might need to stay off overnight.
Servicing
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