CG125W cdi 1998 Turkish

[dx90]

Hi
The bike was running fine and then stared to lose power and pop. Found some splits in the Carb mounting rubber (h 16210-KCS-650) that goes between the Carb and the cylinder head. Replaced with new and the bike is defiantly running better but is still not right.

The top speed is down from 60 to 50mph on a stretch of road I use on a regular basis. So it is not right.

If I pull the throttle back a little to fast it loses power pops and then stalls. It never used to do this before.

The spark plug looks almost white in colour.

Things I have done and checked so far.

1. replaced the Carb rubber mounting and o ring seal cylinder head side with new.

2. Checked fuel tank filter.

3.Took Carb apart and checked all jets were clean and not blocked. (they were clean and so was the float chamber). I also checked the pump/diaphragm for splits and that the pump was working. It looked fine to me.

4. renewed spark plug.

5.Checked valve clearances and they were spot on.

Anyone know what the problem could be?

Thanks

[sickpup]

Have you cleaned the air filter foam. Ever?

[dx90]

No not yet. Had a look at it though and it looked clean enough. Started the bike breathily without the filter and the engine did the same.

[Creepin Moses]

Check the other rubber pipe, from carb to air box, some times they can have little splits in them too.
____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

Just checked for air line cracks/splits and all looks to be Ok.

There is only three pipes on this Carb. Looks like one of them is a breather pipe for the chamber. One for fuel from the tank and the other is for draining the fuel chamber. I think this is correct?

Any other ideas?

Thanks

[Creepin Moses]

Ok, I have the Haynes Honda CG125 1976 to 2007 manual here. When you say The spark plug looks almost white in colour, does it look white and blistered? If it is white and blistered it is caused by an ignition system fault, incorrect fuel or a cooling system fault.
If it's light brown deposits encrusted on the electrode and insulator this would lead to missfire and hesitation. The cause of this would be excessive amounts of oil in the combustion chamber, or poor quality fuel/oil. Hope this helps.
Davey.
____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

It is white in colour but does not have any blistering that I can see.

I have had another look at the rubber connecting the carb to the air box and on closer inspection it does show airline cracks in it but only when squeezed. I have ordered a new one but it won't be here until Tuesday or Wednesday. I will let you know if it works. Fingers crossed on this one.

Thanks

[Creepin Moses]

Why order another one if they are only small splitz you see when you squeeze it, you can fix it with aroldite!. Mix up aroldite then open the splits a squeeze and run some aroldite into the split, cover the area with a smear of aroldite too just to seal it.

If the spark plug is goin a white colour and no blistering, mabey you haven't had it runnin in that condition long enough for blistering to take effect much.
Let us know what happens when you get the new filter pipe fitted, runnit around for a bit with a new plug in it, then let it cool and check the plug.

____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

Ok, will do.

Just checked the ignition system with the multi meter and all values were with-in tolerance exept the HT coil test.

The resistance across the two primary terminals were 0.5 ohms and not the 0.18 - 0.24 ohms that is listed.

Do you think that the HT coil is faulty?

Thanks

[Creepin Moses]

Do you have the haynes manual for the cg1976-2007? If it is this manual have you done all the checks in chapter 7, start at section 22 on page 130. This is all the tests to do on the ignition system (ignition HTcoil test,source coil testsignition pick up test,and cdi unit tests) If you haven't got this manual I will scan the pages for these tests and try and get them up here for you. At the minute it sounds like the HT coil is possibly at fault, but you have to check everything in relation to this just incase it's something else causing it to be at fault.
____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

I have just received my manual in the post yesterday.

I have done all the test in chapter 7 in section 22.

The only one I could not do was check the timing with a strob light. I don't have one.

I have done all the other checks with my multimeter and all the tests were well within range apart from one the Ignition HT coil test.

The Ignition HT coil test reviled he resistance across the two primary terminals on the HT coil were 0.5 ohms and not the 0.18 - 0.24 ohms that is listed at the start of the chapter.
This is the only reading that I got that is out of range from the settings in the manual. I also rechecked the spark plug spark and it looks yellowish and weak.

I have ordered a new Ignion HT coil that will be here on Tuesday or Wednesday.

I want a second opinion before I open the packet and waist more money.

Do you think my findings look correct and that the Ignition HT coil reading points to the coil being faulty?

Thanks

[Creepin Moses]

mmmmmmm, now I am by no expert, but if you have done a second test and got the same low readings there is a fault there, but you say the plug looks yellowish and weak, thats a confusing one to me, going by the book would you say its more brown/tan (indicating engine is good) or light brown deposits encrustig the electrode (excessive amounts of oil in combustion chamber or poor quality fuel/oil) .Also after reading your first post on this topic, have you ever decoked the piston top or reground the valves, this can also result in power loss, it sounds loke its bogging down,also check your choke isnt sticking or the butterfly isnt being obstructed from closing fully, and make sure the throttle needle isnt slightly bent and its at the right setting.
____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

Apologies for the confusion. When I was talking about the yellow and weak plug I meant the spark itself not the colour of the plug.

The new ignition coil arrived today and I have fitted it.
The problem is still their.
The bike runs but I have to keep the revs up high and if I let it tick over it stalls when I pull the clutch in or put the bike into neutral. The engine feels like it is misfiring but I'm not sure. When the engine is could it will tick over. When the engine is hot it will not tick over.

The rubber between the carb and the air box is to bad to fix with araldite, so I have ordered a replacement rubber that will hopefully be delivered tomorrow. Do you think that this rubber would cause the engine to act like this?

If I didn't know better I would say the timing was out but I have no way of checking this.

[Creepin Moses]

Possibly help but it sounds like there is a problem with your choke settings, too much fuel getting in somewhere, thats the choke's job when the engine is cold. When the engine is cold you will automaticly put the choke on,yes, thus letting more fuel/air into the engine, without taking the throttle cable off have a look into the backend of the carb, you should be able to see the butterfly for the choke ( its easier to do this while engine is off) Keep engine off and turn your choke to the on position then the off position make sure the butterfly is not loose and rattling about when the choke is closed. Also make sure bothe the little brass screws on the butterfly are tight. You could also try a higher octane (star grade) of petrol.
____________________
Bomb disposal expert, if you see me runnin, try to keep up.

[dx90]

Just checked the choke/butterfly ect and all is spot on. I can't see anything wrong.
I just put some fresh shell V fuel into the tank and there's no difference.

[robocog]

float height on carb checked after you had it apart?
(easily altered unknowingly if the bowls have been off!)
- unless it was the plastic float type- they are not adjustable according to my book)

Mixture setting on the carb not right?

(assuming CG125-W with PDC4A-A carb)
needle jet clip 3rd groove from top
pilot screw 1 3/4 turns out from closed

try a gunsons colourtune (glass spark plug) to see what the spark looks like when running and adjust the pilot screw to get a good mix? and to get a good visual clue as to whats going on in there?

No leaks in exhaust anywhere?

Double check the inlet is not leaking, squirt water round the rubber inlet at both ends whist engine is running to see if the rpm changes
(use a squeezee bottle or something to make the test more controllable rather than randomly chucking a bucket of the stuff

Sure I read somewhere (could have been the Haynes manual) to try and avoid removing the carbs from the rubber due to poor seal potential and always remove rubber from head with carb still attached

seemed a bit odd when I read it - but someone wrote it for a reason and it has stayed with me - if you did this did you replace the o ring and troque back up properly (perhaps with a smear of something to ensure a good seal?)

Is it the accelerator type carb?
Any splts in the diaphragm or boots?
did you take out the ball bearing one way valves?
maybe worth checking they all went back together properly using an exploded diagram

On the CDI models I don't think theres anything to adjust timing wise (as its done by non movable pickup and black box?)
So if you think the timing is not correct another CDI and pickup is the only thing you can do to correct it as far as I'm aware

Do let us know how you get on
there seems to be a few threads that never seem to have a conclusion...not even replies of "got sick of the problem so set fire to it"

Regards
Rob

[dx90]

Hi Rob.

Just followed all your instructions and now I have a different problem.

After completing all and reassembling It starts better but when the bike is cold it stalls until it warms up.
Once its warm and done a mile or so, all power drops and the bike come to a stop and the engine will not start.
If I leave the bike for a couple of minutes it will then eventually start again and then I get lose of power all over again a mile or so down the road and so on.
The bike will get about 11/2 - 2 miles before losing full power down to a stop.

[robocog]

Stalling after a short distance...
Fitted a new petrol cap just prior to this happening?

Could be vapour lock
when it stalls just pop the petrol cap off and listen to it and see if you can detect a vacuum in the tank
(breather hole in cap blocked? or missing if new!)
try running with the cap loose on a short and careful run and see if fixes it?

Could be a few other things, blocked fuel filter (in petcock on that model maybe?)

kinked fuel pipe?

Of course it could be something else but from the description it was my gut reaction long distance diagnosis guess

worth twiddling the fuel mixture out a little to see if you can improve the cold start, especially as the weather is not cold in the UK! think they are failry aggressive so keep it to only a small fraction of a turn at a time and run it a little between twiddles

My Brazil CG has not required any choke to start in the mornings and it lives outside

alternately a ball park way of seeing what the engine "wants" if you dont have a colourtune handy to see the colour of the spark

run engine to operating temperature (eg let it fully warm up first)
with the bike idling
twiddle the mixture screw inwards slowly till engine gets a bit stumbly
Then slowly count the fractions of turns as you screw the twiddly out till engine gets stumbly due to excessive fuel (too rich) the ideal ammount of turns for the pilot is somewhere roughly half way between these 2 points
(best- "SAFER" to keep it slightly on the rich side rather than lean as lean will kill the engine rather quickly!)

Looking at making the plugs a nice tan colour for ideal situation - but hard driving/accellerating will not acheive this regardless of ideals of mixtures, so keep the riding smooth if doing plug pulls to "read the mixtures"

Regards
Rob

[dx90]

The petrol cap is original. I have replaced the CDI unit but not the pick-up. There is no change, so CDI unit itself musk be OK.
I have reset the idle screw.
I have taken a photo of the spark plug. Hope it uploads OK.

[mr rip]

oh dear, that plug looks pretty well burnt out

the gap also looks pretty excessive

if it's loosing power when it gets hot it's more than likely, either weak mixture or fuel starvation

when it gets warmed up & starts to slow down try giving it a little bit of choke, if it starts to pick up a bit then you carb needs adjusting

if you have splits in your mounting rubbers then that is probably why, try spraying some WD40 on the rubber while the bike is running if the revs pick up then its definitely leaking
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[dx90]

The gap is correct and the plug looks very much like it did the day I bought it. Just coloured with use. The plug is a Iridium spark plug and you can't see the middle pin very well, that's why the gap looks excessive but I've just doubled checked and the gap is fine. I did put a new plug NGK plug in but it made no difference so I went back to the Iridium that I always used. If you think I should go and buy another one let me know and I'll go get one?

What about the colour of the plug, does it look as it should if burning correct?

Tried the choke, but it makes things worse not better.

I have just tried WD40 and I have no leaks.

[mr rip]

it looks better from that angle now I can see the electrode it looked like it had burned away in the other shot

the colour looks about right for a correct mixtue & the fact that giving it a bit of choke didn't help would sudgest that all is well with the carbbut it does look a bit crusty & I would give it a good clean befor putting it back in,

the next thing I would suspect is over advanced timing

one way to test for this is to slow down to a crawl & try to accelerate in too high a gear ie 4th or 5th if you hear a knocking or ratteling noise like you have marbels in your barrel then the ignition needs retarding a little
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes

[dx90]

I deleted this post because it double posted.

[dx90]

I will give it ago. The timing on this bike is done buy the CDI unit. I have just changed this and it made no difference.

robocog did say change the pick-up as well I haven't done this yet. I wonder if it could be the pick-up?

I have changed the mounting rubber that joins the carb to the engine. The old one had splits in it.

I have just changed the rubber from the carb to the air box. The old one had splits in it as well.

I have taken apart, cleaned and reset the idle on the carb twice now.

Tested all the ignition resistances as in the Haynes manual and there all as they should be apart from the ignition coil. That has been changed for a new one.

I tried a new spark plug. It made no difference.

I have made sure the tank filter is clean. It was.

I have sprayed WD40 and there is no sign of any leaks.

I have cleaned the air filter.

I have just drained all fuel from the tank and filled with fresh new. Just in case it was contaminated in anyway.

The plug colour seems to be OK. It has always been that colour with no change.

I have checked the petrol cap and that seems to be breathing fine.

I have checked the valve clearances. They are fine.

The exhaust is in new condition with no leaks.

I have checked the oil level and that is fine.

The bike was running fine and then got worse really fast over a two day period.

I am totally in the dark with what is causing this. I don't know what to look at next.

[mr rip]

it sounds as if you've covered nearly everything it could be already

have you checked the plug cap yet?

if your getting a weak spark I would suspect the HT circuit befor the LT circuit but the pulser coil could still be at fault & it sounds like the only thing you haven't changed yet, check the air gap between the flyweel and the sender coil, if they have been rubbing at all then it could have burned out

another possibility is the flyweel magnets could be weak but that would normaly only happen if they were given a realy hard bang

the only other thing I could think of would be to check the exhaust isnt blocked, usualy more of a problem with 2strokes, but it could still happen
____________________
never criticise a man until you've walked a mile in his shoes, then when the muck hits the fan you'll be a mile away & you'll have his shoes