125 Kx125

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Yamyhopper

i just got a 95 kx125 with a fully rebuilt engine and the previous owner said he richnend up the mixture for break in I was riding and I got into 3rd gear and the bike just shut off so I pushed it back and I noticed like gassy oil puddle underneath where the pipe and silencer meet. So I took them off and noticed a that the gassy oil would run out of the pipe. So is that because he ran it rich? Should I let it air out overnight? I tried to start it and it would only run off of carb cleaner after that burnt off it would shut off
 
Mihylo33

Mihylo33

Right now by your description I can only imagine that the plug is loaded up and the engine is also flooded.
Install a new plug and clean the carb twice. While you are in there set the float. Directions on how to set the float will be in your service manual. If you don't have a service manual, get one. To get you by or if you are having trouble understanding the process you can Google dirt bike carb cleaning and you'll find basic videos on the subject.
 
2Wheels

2Wheels

For that reason I would rather buy a bike with 30 hrs on a "rebuilt" motor than 0. If you start with a strong runner it's easier to narrow down the problem. While you have the carb off check the reeds. How is the compression? How did it run before it shutdown, and were you in high revs or putting? If it was revved out its probably not a fuel problem, and if it wouldn't rev then there's yer sign.
 
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ossagp

How rich is richer? Was his idea of running it richer for breakin adding lots of oil to the premix? If you are getting too much gas and have little knowledge of what was really done, ie you werent there and there is more than a good possibility that the PO/rebuilder was also in the dark I would take the caburetor apart, inspect the float and needle and reset them to factory. I would also compare the jets to factory and get as close as you can to factory specs.

I would also NOT ask another question regarding similar situations without a really good description of what the spark plug looked like when you took it out. A picture is better. ("I put in a new one before I started it" and similar responses are not the kind of things I call a description.)
 
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Yamyhopper

So it turns out I had the gas on "on" and jt was low on gas (I feel dumb) anyway I still got engine oil coming out of the exhaust. I believe It's crank seal leaking oil because I do not not as much power as I normally would
 
SRAD97750

SRAD97750

Moderator
Staff member
Yamyhopper:
So it turns out I had the gas on "on" and jt was low on gas (I feel dumb) anyway I still got engine oil coming out of the exhaust. I believe It's crank seal leaking oil because I do not not as much power as I normally would
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Fuel/Oil mixture from the exhaust port, and lack of power screams improper float setting. A simple case of "what goes in, must come out."
Clean the carb while you're inside it. -BIG DAN:thumb:
 
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ossagp

Yamyhopper:
So it turns out I had the gas on "on" and jt was low on gas (I feel dumb) anyway I still got engine oil coming out of the exhaust. I believe It's crank seal leaking oil because I do not not as much power as I normally would
Click to expand...

I would bet any bike that old has some bad seals. I would also bet that yours has a slobbering carburetor. If you watched any of the motocross or supercross races from the past, in the pre injected days (5 years ago would be far enough back) you saw guys winning races on carbureted bikes. Those rigs had the floats set at least once before each event. Yours may have last had it when the carburetor was made.
 
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Yamyhopper

I ordered the seals and I will check float height. But the oil coming from the pipe doesn't smell gassy and it's not flammable (unlike gasoline)

So I'm leaning more towards bad seals
 
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ossagp

Yamyhopper:
I ordered the seals and I will check float height. But the oil coming from the pipe doesn't smell gassy and it's not flammable (unlike gasoline)

So I'm leaning more towards bad seals
Click to expand...

That had to be fun to watch. Sorry that I missed it. Yeppers, I bet that float is dead on!!!!!!!!!!!!!!!!

BTW, did you research what changing the primary side crank seal involves. I mean I know you are on top of this, but did you check?
 
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Yamyhopper

ossagp:
That had to be fun to watch. Sorry that I missed it. Yeppers, I bet that float is dead on!!!!!!!!!!!!!!!!

BTW, did you research what changing the primary side crank seal involves. I mean I know you are on top of this, but did you check?
Click to expand...
I've never done it on a kx125 but I've done countless times on other bikes
 
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ossagp

OK. So you might want to do as I suggested then. (Quite a few KX's have the primary side seal contained on the bearing side of the case, so splitting the center cases is necessary to change it. I have not done a 95 kx of any size so I am not sure if yours is so affected.)
 
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