More problems on mates XR400....Wet black oil coming out exhaust?

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pdee4t

Hey guys. Having more issues with my mates XR400. Not sure what the causes would be but his 1998 XR400 is now leaking wet oil from the muffler.
Only just started happening.
To me it sounds like somethings not burning properly or could be a cracked head gasket or crank or valve seals? Or seals of some kind...?
What else would be a possible cause for this?
 
Mihylo33

Mihylo33

any stuttering, coughing or bogging?
has it been ridden hard since the last issue.
Run it a little hard and get that exhaust hot and burn out any residual fuel and oil remnants from inside the exhaust.
 
P

pdee4t

im just going to do a compression test on it tomorrow guys.
he doesn't have an air compressor so I can't do a leak down test. A compression test is all I can do on it. Wet and Dry.
 
O

ossagp

The compression test won't tell you anything about the valve seals and guides. Those get my vote as the most likely. Usually a bad oil ring on a three ring system has to virtually be gone to make things wet. A compression test tells you more about that. Bad valve seals can show "wet" sooner in my opinion. For the rings to do it you have to get it hotter, rev it higher and back off of it to get the vacuum up. It will smoke badly if someone is watching. Plan on tearing this one down soon. If the seals are bad (valve seals) that means the guides are too.

Lots of times removing the header pipe and examining the valve stems for an oil trail works.

Lastly, could your engine be grossly over filled?
 
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Mihylo33

Mihylo33

before I did all that I would just ride that bugger really hard get that pipe nice and hot and burn out all the crap out from inside. then change out the exhaust packing since that will be saturated.

had a buddy complain about splatters on his white fenders when he started his bike cold. could never reproduce it until the next weekend ride. It turns out he was getting water in the pipe while washing it before putting it away
 
P

pdee4t

i went to check his bike out today.
there wasn't an actual leak like I thought there was. He took the end cap off the muffler, and there was a little bit of wet black liquid in the middle part of the muffler.
I think it might've been fuel, possibly caused from running a bit too rich. there wasn't very much at all, just a slight little dab of liquid.
He explained it to me like it was leaking out, but it wasn't leaking out at all.
the bike starts and runs fine, as normal.
 
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ossagp

Mihylo33:
before I did all that I would just ride that bugger really hard get that pipe nice and hot and burn out all the crap out from inside. then change out the exhaust packing since that will be saturated.

had a buddy complain about splatters on his white fenders when he started his bike cold. could never reproduce it until the next weekend ride. It turns out he was getting water in the pipe while washing it before putting it away
Click to expand...


besides, that is more fun that testing ANYTHING!
 
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