cg125 engine

[donkey]

Hi all ive just bought an old maid of a 92 cg125 and im having major problems getting the engine to run properly it seems to be running really rich and fouling the plugs (plugs aleays look black and sooty) yet earlier today i took it for a run up to about 45 or 50 mph for about 15 mins then it seemed to over heat and cut out when i looked at the plug it was white as though it was running to lean i have since let the bike cool down and taken it for a run up the street and now the plug is back to being black and sooty heres a list of what i have done

stripped and cleaned carb pilot screw is set to 1 3/4 turns as per manual
cleaned air filter
set valve clearance
new plug and cap
new oil
new petrol
checked ponts they look fine

anyone have any ideas

also im thinking about putting another engine in it if i can find one that i can afford (anyone know of one thats going cheap) can i just drop an engine in from any cg125

[simon1221]

Check for fuel blockage in he pipes, it sounds like you are getting too much fuel at first, then not enough later on, this would explain the strange plug problems. Check all pipes from tank to carb (do 4t have carbs?) check fuel filters in the tank if you can be bothered.

It may be worth cleaning the carb as well.

Be aware that the standard setting on the manual would be for when the engine is new, over time the mixture will have to be adjusted (but only very slightly) to compensate for wear etc.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[stinkwheel]

The choke switching off properly? There is a little sprug flap on the choke butterfly valve on a lot of hondas, the spring can break letting it flap down all the time.

Other suspect would be the throttle needle. Is it in the right position, firmly attached to the throttle valve, bent, damaged etc.?

The points may look fine, but are they opening in the right position? Check the timing, make sure the auto-advance is working properly if CGs have them.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Whitetrash]

definatly check that needle!!!!! give the carb a really good clean as well, check the floats
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No body likes me,
Every body hates me,
Think I'll go and eat worms!

[donkey]

I have checked the needle its set 3rd from the top which is where the manual says it should be i was also advised to drop it one which i have tried but didnt seem to make much difference maybe i should get a new set of points tomorrow and try that o and i have checked the choke switch and thats fine

[Whitetrash]

choke switch or the whole mech????? have you checked the flat height???
____________________
No body likes me,
Every body hates me,
Think I'll go and eat worms!

[donkey]

i have just found an engine for sale out of a 2000 model will this fit into my bike and does £100 sound about the right money for this engine

i will check everything on the choke when it stops raining

[Scotsman37]

That engine might not be in that good a condition or missing several electricial attachments, covers and what distance it has been used for?

Cheshire Motorcycles have an engine and here's there link and info;

https://www.cheshiremotorcyclesalvage.com/acatalog/

CG125W CDI 1998-2001 E25031H

Price: £250.00

ENGINE COMPLETE WITH ALL ELECTRICS AND COVERS
7400 MILES GOOD RUNNER, BIT DIRTY.

You could ask the ones at Cheshire motorcycles if it would fit a 92 honda ?

[pipnet11]

Is the air filter there (and oiled if they need it)?? may sound obvious but thats what caused the lean running on my GS125 when I first got it.
____________________
I love the girls that do, I hate the girls that dont, I hate the girls who say they will and then they say they wont, but the girl I like most of all and I think youll say Im right, is the girl who says she never has but looks as though she might. - Max Bygraves

[stinkwheel]

An old engineer once told me that 70% of carburettion faults are electrical. He is someone who knows what he is doing.

Check that timing!
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[donkey]

acording to the manual the timing can only be adjusted by way of the points which the manual says should be .3 which they are
i bought the engine i mentioned in my earlier post the bike it came from had 4500 miles on the clock but it was a cat b write off it had been stolen then crashed while being chased by the police anyway for my money i got the engine carb wiring loom some electronic gadgits and back wheel the wiring loom has been cut and my manual doesnt cover this model does anybody have a wiring loom diagram for a 2000 bike thery could let me look or would the stator plate and flywheel from my old engine with the points go in the new engine it would save me having to rewire the whole thing

[ts50x0]

if the engines a cdi it wont fit
this sound most strange and youll probably lagh but try this,
you want to get a peice of card and jam it in the top if the air box housing, pm me if you take me seriusly so i can explain more, if your not going to take me seriusly then i cant be arsed to explain the whole crazy thing, and beleive me thats what i thought untill it made my cg that was running rough and hot run perfectly.