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04 kx250 oil coming out crankcase vent hose

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Hi all...

So I replaced the cylinder, piston and rings with an athena top end set (all new) on my 04 kx250 f. After starting it and idling for a few oil started coming out of the crankcase vent hose? I put 1300cc of oil in it so not over full.

Ran it up and down the street and it literally had oil everywhere on the rear section. Any ideas what I did wrong ?

THANKS!

 

Sent from my SM-S903VL using ThumperTalk mobile app

 

 

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2 hours ago, MaybeMe said:

Also, did you replace the cam chain and reset the tensioner?

The KX is a 2T

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24 minutes ago, 1gr8bldr said:

The KX is a 2T

His title isn't correct. He mentions a 250f in his post and afaik, 1300ml is way too much for any 250 2t.

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4 hours ago, MaybeMe said:

Keep an eye on the oil level. It's normal on those Kawis after a rebuild since if you change the oil, it goes right near the vent hose area and will piss out the vent hose. 

It should be okay as long as it stops.

https://thumpertalk.com/forums/topic/271592-oil-coming-out-of-brether-hose/

I have rode it 3 or4 times and it hasn't got better. I can ride it maybe 1/2 mile and it just pours about 300cc of oil out

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43 minutes ago, MaybeMe said:

His title isn't correct. He mentions a 250f in his post and afaik, 1300ml is way too much for any 250 2t.

Your correct it is a four stoke.

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4 hours ago, MaybeMe said:

Also, did you replace the cam chain and reset the tensioner?

The timing chain has probably 10 hrs on it from when I also put a crank kit in it and yes I did reset the tensioner. 

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Did you also drain oil from the clutch side? There is a 14mm and an 8mm bolt. You could be overfilling it if all the oil doesn't drain.

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Yes
I was told by a shop that it was probably the crankcase vent reed valve, so I had to split the cases and it was fine but replaced it anyways. Some said it sounded like the compression ring was upside-down, so I took it back apart , but the athena ring originally had a ink stamp mark to indicate the top side of ring and after running it the ink mark was gone,but I'm sure it's correct. The only thing I can think of is that the new cylinder was totally Smooth (no hatch marks) and after I started it and oil came out ,several times doing this that maybe the ring didn't seat properly?

Sent from my SM-S903VL using ThumperTalk mobile app

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2 hours ago, Wessco said:

Yes
I was told by a shop that it was probably the crankcase vent reed valve, so I had to split the cases and it was fine but replaced it anyways. Some said it sounded like the compression ring was upside-down, so I took it back apart , but the athena ring originally had a ink stamp mark to indicate the top side of ring and after running it the ink mark was gone,but I'm sure it's correct. The only thing I can think of is that the new cylinder was totally Smooth (no hatch marks) and after I started it and oil came out ,several times doing this that maybe the ring didn't seat properly?

Sent from my SM-S903VL using ThumperTalk mobile app
 

Did the cylinder come with any break-in instructions from Athena? Sounds odd that any cylinder would ever come without cross hatches.

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