Honda CG125 General
How to stop your engine from clogging up
Choke when the bikes been standing for several days
Never use a pressure washer to clean any motorcycle, water can get in to wheel bearings and in to the electrical system.
You can adjust the Gear Change Lever height to the size of your boots or shoes.
The dealers often set it pointing down, which is totally wrong for a Honda CG125 since the riding position is upright, not forward.
The Owner's Manual shows the gear change lever pointing level with the foot rest (not pointing up or down).
I found this to be correct for my boots and expect it to be the same for most people.
To adjust the gear change lever, remove the nut bolt, take the lever off the bike and put it back on in the correct position,
put the nut bolt back in (if you do not put the gear lever back far enough or to far back, the bolt will not go through).
Adjust the Suspension to the weight you are carrying.
There's probably 5 settings on each side of the bike.
Make sure both are on the same setting.
You can adjust it by turning the bottom of the suspension around.
You may be able to turn it with your hands if you are strong enough,
if not use the spanner (may need the extension shaft) see How to find your bikes Tool Kit and Owners Manual in the Servicing page.
When the suspension is new, the lowest setting (opposite to stiff) is not normally used since its for light people with smooth roads.
The standard setting is the one above the lowest setting.
The maximum setting (stiffest) is for carrying a passenger.
The correct Suspension setting for you will depend on your weight and how old / worn the suspension is, all springs age / wear and drop in stiffness.
Its simply a matter of trial and error, it will effect how well the bike handles round bends and handles bumps in the road.
How to stop your engine from clogging up
It’s a good idea with any engine, if it’s only been on short trips, like 5 miles to work, to take the bike for a long fast ride to clean it out.
Any engine that does not get up to full temperature (slow engine revs or short trips) will get condensation inside and burning deposits will build up excessively,
that’s why you have to change the oil more often in these cases, but you still need to blast the bike out, it can also help the chain.
Lots of people think the Honda CG125 has a very small engine,
so it will get up to full temperature very quickly and its engine speeds are much higher in normal operation than larger engines.
Well the temperature takes a lot longer than many think, 5 miles just does not get it up to full heat.
I have noticed that if you do loads of 5 mile trips at 40mph in 5th gear the bike suffers.
But when you take it out for a 50mph or faster run, of at least 15 miles it cleans it self out (you still need to change the oil more frequently).
You may notice the bike starts better, idling is faster and healthier, less vibration, smoother and more power.
If you do a lot of short, slow trips try to have a long fast one now and again.
You can also buy better quality petrol that has extra cleaners in to reduce the problem (see Petrol below).
The choke lever is underneath the left hand side of the petrol tank.
When the lever is up the choke is on and down its off.
A few of the Front Drum brake models have reversed the choke lever so down is on and up is off.
The Choke on some Front Drum brake models may not be needed in summer (when the outside air is hot).
The following is for the front disc brake model, this may not be true for older models (since their emission controls are not so strict).
As long as you have the Idle Mixture Screw and Idle speed screw set right (see Servicing page) all the following is true.
Choke lever up is on and down is off.
Half choke is never any real use, bike still needs full choke on a hot summers day.
The bike has a very small window of when half choke works like 2 seconds or never.
Never leave the choke half on when the engine does not need choke, over time it will damage the engine, the bike will not stall when idling with half choke.
Full choke is not strong enough when engine is stone cold in the middle of winter, you have to generate heat by turning the engine over a few times,
below 10c a small heater is also activated to help.
To start the bike from stone cold, put choke fully on.
Open the throttle 1/8 to 1/4 turn while pressing the starter button (see Choke when the bikes been standing for several days below if hard to start).
When the bike starts, you must keep the revs up or it will stall. The bike will never idle when the choke is fully on.
If you get the bike hot enough for it to idle without choke, you may find the bike stalls when you open the throttle,
simply restart with full choke, this will happen when the bike is almost ready to come off choke.
When the engine is stone cold, it will need choke for a long time.
I advise you to warm the engine up (choke on) while riding the bike, unless your not experienced with controlling the bike.
Riding the bike with the choke on is easy, until you try to change down a gear since you will probably try to let the engine idle,
when of course it will just die. The secret is to make sure you keep the engine revs much higher than idle to stop this.
Finding the choke lever while moving takes practice, try with thin or no gloves to begin with.
If the bike has been switched off for a few hours, put choke fully on, start the engine (1/8 to 1/4 throttle), blip the throttle 3 or 4 times and turn the choke off.
I advise you to warm the engine up (choke on) without riding the bike since it's only 3 to 4 blips of the throttle.
Choke when the bikes been standing for several days.
See Choke above before reading the following.
The following is for the front disc brake model, this may not be true for older models (since their emission controls are not so strict).
The petrol evaporates over time.
If you use it every day, the bike will usually start first turn of the motor.
If its been standing for a few days, it will take more turns of the engine, every day can add an extra turn of the engine (sometimes).
At worst it could take around 10 turns.
For every 5 seconds that the electric starter is used, you must give it a 10 second rest.
I have found it best to turn the engine over once, let it rest for 2 seconds and try again, keep repeating this sequence until you hear it fire.
If it fires once and then dies, try
the same sequence again or
try turning the engine over 2 or 3 times without a rest or
turn the engine over with the throttle closed (as soon the engine fires, open the throttle 1/8 to 1/4 turn to keep it going).
If the bike really refuses to start and keep going, switch the ignition key off for 30 seconds or so to let the battery recover to full voltage, then try again.
If you have flooded the engine with petrol, switch the choke off and open the throttle fully and turn the engine over several times.
When the bikes running, the petrol in the carburettor is still partly stale (gone off / evaporated),
expect the bike to need choke for longer than normal and to feel rough,
until the carburettor has been fully refilled with petrol from the tank (could take 0.5 miles).
All this trouble might be eliminated if you leave the petrol tap on all the time,
but mechanics warn that over time the petrol will seep out and fall all over the bike and floor.
The gearbox was improved with the front disc brake model, so the following may not be true for older models.
When you are in 5th gear and want to change down to 3rd or below, you must let the clutch out in 4th gear.
If you do not, the gearbox will refuse to change down to 3rd or below, until you let the clutch out (in 4th gear) and then in again.
If you are stuck with this problem at a standstill,
briefly let the clutch out and back in again before the bike stalls, or rock the bike forwards and backwards while blipping the throttle.
When the fault is fixed you will hear a click.
This is probably a design safety feature to stop you travelling at high speed in 5th gear,
and changing down to a low gear and letting the clutch out while still at high speed,
which would lead to excessive uncontrollable engine braking on the back wheel.
The gearbox / clutch will overheat if for instance, you race from one set of stopped traffic lights to another a short distance away in the hot summer.
You will not have any problems if you let the clutch out in every gear when changing down, but the gearbox will refuse to change down if you do not.
When it refuses to change down and your stuck at a standstill,
the only ways to fix it are to let the clutch out briefly (pull it back in before the engine stalls) or wait for things to cool down,
you will hear a click when it's fixed.
The front disc brake model has a petrol meter and a redesigned petrol tank, unlike the front drum brake model.
The following is for the front disc brake model.
The petrol tank holds 13.5 litres = 3 gallons.
The petrol meter reads flat out full until the first gallon (4.54 litres) has been used.
When the petrol meter needle is half way between full and empty the tank is half full.
If the petrol tap is set to on (not reserve), the bike will run out of petrol shortly after the needle has gone past empty and gone off the scale.
The bike will normally run out of petrol when the bike is slowing down, not speeding up.
It then takes around 10 turns of the starter motor to get the engine running, by using the reserve position on the fuel tap.
I have always opened the throttle 1/8 to 1/4 turn when pressing the starter button, but it could be worth trying with the throttle closed after a few turns.
You may need to rest the starter motor for 2 seconds between some of the turns, or even switch the ignition key off for 30 seconds to let the battery recover.
I advise against running out of petrol since this takes a long time and holds up traffic.
Without reserve the bike seems to run out of petrol when there is still 3.5 (normally) to 2.5 litres still in the bike,
unless it runs out while not slowing down. I have run on reserve until there was only 1 litre of petrol in the bike.
Reserve officially holds 2.3 litres.
In the UK I have never noticed any substantial difference in normal unleaded petrol between the brands,
engine performance and fuel economy did not change.
But super unleaded is much better than normal unleaded in this bike engine.
The effects of super unleaded and the different makes will depend on the engine design,
the following results are from the front disc brake model,
another make or model of bike / car engine, might have less improvement or no noticeable improvement or improve even more.
I started off with Sainsburys super unleaded which is only 2p a litre more than unleaded,
the bike increased in power, torque (pulling power) and the engine ran smoother.
The improvement was largest in the lower and mid rev range of the engine.
I then tried Shell Super (it's called V Power, the old version was called Optimax) that costs 7p a litre more than normal unleaded.
The Shell Super improved my petrol consumption by more than 7p a litre,
the bike increased in power, torque (pulling power) and the engine ran smoother.
The improvement was largest in the lower and mid rev range of the engine.
That was all compared to the Sainsburys super unleaded.
I would say the jump from normal unleaded to Sainsburys super was small compared to the jump to Shell super.
The Shell super also kept improving all of the above the more I used it, it took a tank or two before it slowed the improving down to a crawl.
It does claim to have extra cleaning powers to clean out your engine and improve all of the above.
It also significantly reduced the amount of time the choke is on for.
You can mix any super unleaded brand with another brand of super unleaded or normal unleaded,
but expect the improvement to only be 50% if you only have 50% super with 50% normal unleaded.
If Shell is not available near you, try BP Ultimate or Tesco 99.
How Shell V Power, BP Ultimate and Tesco 99 compare to each other is hard for me to say.
The best way is for you to test them yourself. You may or may not find a large difference between them.
Watch out for fuel consumption, cleaning and performance differences.
I went back to Sainsburys super (put nearly a whole tank of it in), immediately the bike lost most of the Shell V Power differences.
But as I used more and more of the Sainsburys super in the tank, the bike got slower and slower (no Shell V Power to keep it clean).
When I was down to half a tank, I filled up with Shell V Power and got half the benefits back.
This proves the engine was being cleaned by Shell V Power and Sainsburys Super was making the engine dirtier, like normal unleaded.