cracnk case breather full of oil
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  1. #1
    Member Davecb1k's Avatar
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    cracnk case breather full of oil

    :: apologies for the misspelling of crank - Im using a 40inch tv and sat 6ft away, and Im educationally retarded ::

    Good evening one and all,

    Well I would like to explain the minor issue I seem to be having with my 11 plate.

    It has a LeoVince SBK decat/end pipe and a K&N (no Power commander)

    I use it for my commuter so it get the brunt of the good and horrendous weather - I spend most of my life between 2/3 gear and at about 2-4krpm (approx 30/40mph).

    I have noticed it judders like a jack hammer, and rides like a twin (so much engine braking!!) - which isnt the worst of it, it seem like every week I have to pop the covers off and empty the crankcase breather as it fills up with oil, today the bike totally died filtering traffic doing about 40 after a cough a splutter and a final fart. but fired up perfectly and was running fine again. Now I've cleared out the breather It hasnt missed a beat and runs beautifully!

    So my questions:

    1) Why would the crank case be over pressurising so much it fills up the little plastic tube thing after ~100miles? (excuse my technical terms)
    2) Do you think in your opinions the fact the fuelling is out as it has no power commander over pressurising the crank, or could the pressurisation be affecting the fuelling?! (or is it a loop of both)


    As always I appreciate your comments and advice please feel free to throw what ever ideas you have out there!

    Thanks Guys,

    Dave.
    Last edited by Davecb1k; 10-08-2015 at 03:51 PM. Reason: bad spelling

  2. #2
    Senior Member 20fingers's Avatar
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    I have leo Vince decated and no power commander ,standard air filter and it has been running fine from 2009.

  3. #3
    Member Mitch's Avatar
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    Usual causes are overfilling engine oil or valves ?

    Mitch

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  5. #4
    Senior Member COLVERT's Avatar
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    Crank case pressure is generated by blow past of the piston rings from the combustion chambers.

    Maybe your piston rings are getting past their best.---
    Personal Disclaimer:
    My thoughts are intended to provide a sounding board for your own.
    Some of what I say may go against your own thoughts and may seem harsh, targeted and malicious.
    This is not my intention – I am simply using my experience, including other peoples, as a way of debating and giving advice - of which there is no guarantee that it's correct

  6. #5
    Senior Member Eldon's Avatar
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    Was it run in too gently?

  7. #6
    Senior Member doser's Avatar
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    Dave, sorry lad, but I don't think this sounds like a "minor issue". The problems you're describing should simply not be happening on a properly functioning engine.

    As to the underlying cause, other posters have identified the likely sources. There's an easy way to check 'blow-by': simply run the engine with the oil filler cap off. Normally there is a small amount of 'pumping' of air out of the cap; about like blowing on your hand medium-hard. And it should be very easy to screw the filler cap back in place, while the engine is still running. If the crankcase is pumping 'hard', there'll be a BIG stream of air, and the pressure will make it difficult to replace the cap ( I experienced this with my previous SV650, when there was a lot of blow-by when the rear cylinder valves were failing).

    Good luck!
    piling the mileage on...

  8. #7
    Senior Member DELuth's Avatar
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    An overfilled crankcase would do all of that. Are you sure the oil level is ok? Are you checking the oil on the sidestand?
    "I don't know how to put this, but I'm kind of a big deal. People know me. I'm very important. I have many leather-bound books and my apartment smells of rich mahogany."

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  9. #8
    Member Davecb1k's Avatar
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    Hi all,

    Thank you so much for you replies,

    I have checked the engine oil and it's on the lowest line (I also assumed it could be too much oil)

    Good suggestion about the filler cap though that's next, I'm hoping there is an airlock or something cheap.

    My next steps will be to drop the oil and change the filter for a new standard filter, replace with castrol 10-30 as per the manual. I am hoping the filter is blocked or something!

    The bike itself has only done 5k miles, do you think the rings could be going sounds like it's going to be expensive! Or it not a milage thing but a wear thing?

    As always thanks so much for your ideas and suggestions!

    Cheers,

    Dave

  10. #9
    Senior Member Eldon's Avatar
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    At that mileage a fault sounds much more likely.

    Can we assume that somebody hasn't removed or blocked the wrong pipes when fitting the after market bits?

    Check the breather from the rocker cover.

    My comment on the running in refers to what is known as glazed bores this could be the answer but I would exhaust the other possibilities first.

  11. #10
    Senior Member Hudson's Avatar
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    wow....5k and an 11 plate..... do what the more experienced spanner guys say then if no luck get it into someone who knows what the hell is going on !

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