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749 Crank Case Breather

Discussion in '749 / 999' started by Spjallen, Oct 21, 2017.

  1. Not sure about power loss, it's just the pressure I want to reduce. This is an addition rather than a total change.
     
  2. I had the same, thought was the clutch seals leaking but no its the standard catch can that cant keep up with it, you can try and clean it and so on but as soon it has a bit of oil it tends to leak a bit and due to the clutch is just behind it leaks onto it..
    Mine doesn't use any oil at all and only does TD. I made my own catch can as I believe the original design doesn't help as the reed valve doesn't allow the oil in the pipe to return and the little hole in it is just not enough, I removed the valve at the crank, a different hose that goes up instead of horizontal then closer to the return to the airbox I put a one way valve.
    I also read somewhere that this is a common thing for xx9s that are only riden properly ;), on track.
    Hope it makes sense.

    Ric

    Catch can.JPG
     
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  3. Have you been on track with it since? Did it work?
     
  4. To be honest no, I ran the bike and took her for a spin but that’s it. I’ll keep you posted when I do.
     
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  5. kit came Friday and was on yesterday. A very simple job apart from one fiddly seal in the breather. Hopefully get it tested next week ( probably on the dyno as it needs to be done under power ). Only slight criticism is the kit only comes with one securing grub screw. I think I'd prefer two more - they are only 99p on eBay for 5!

    Crankcase breather revision.jpg
     
    #25 Spjallen, Nov 5, 2017
    Last edited: Nov 6, 2017
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  6. Please show some photos when it is fitted, very keen on how that contraption loks like and also interesting to see how it works.
    Did you order it from Moto Rapido, i couldnt find anything when i looked and that why i did the tank.

    Cheers

    Ric
     
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  7. Will do. Yes, got it from Moto Rapidio. If you're a Ducati Sporting Club member you get 10 % off too!

    This is the contact I have [email protected]
     
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  8. So how did you get on with the kit? well worth it?
    I not been out with mine, loads of sh1t going on and tracksdays went done the drain.
    One question, the kit removes the reed valve... no more valve at all, by what you said before and photos of the kit there is not valve anymore.

    Ric
     
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  9. Yes it gets rid of that valve. TBH I've also not been out racing with the Ducati since the addition. Ran it up loads at home and all seems fine. Is it worth it? Difficult to say as I've not been on track but it's not exactly a foirtune so quite happy.
     
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  10. This is the same kit that I’m about to fit to my fettled 999r engine. I had a slightly different issue where the case pressure was enough to blow oil out of the top of oil pressure sender.

    I’m going to remove the sender and replace with a blanking plate and fit the kit to manage the oil pressure better. The problem typically occurs where high revs are maintained for a long period.
     
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  11. Basic system is enhanced. This kit adds to the reduction in crank pressure.
     
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  12. Yeah, hopefully it’ll reduce it enough
     
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  13. when are you next on track? It would be good to analysis and compare the data after.
     
  14. I’m out on a European track day in October and November, but may get a UK day in beforehand. I’ll post as soon as I’ve been back out.
     
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  15. The “excessive” crank pressure is still giving me grief under high revs. It blows oil through the clutch push rod seal / o ring. Changed ALL clutch side seals including the large one on the clutch housing. I’m going to check the little oil seal on the push rod should be a spring seal (8/12/3) not an o ring and modify the crank breather. I’ll keep you posted as I don’t want to waste another track / race day.

    BE2BA862-F887-4B2B-930E-BFB7E531ABAA.png

    F2A75831-5652-4882-816A-28CC22691B2F.png
     
  16. Having the exact same problem with my 749R race bike, quite some oil on shoe, frame and dripping of the bottom of the clutch after a tough session. Replaced all clutch rod seals beginning of this season but problems still there.
    Did you have any luck?
     
  17. You definitely need the breather system referenced above, and the 749 & 999 series really suffer from excessive crankcase pressure.

    Speak to Rich at Louigi Moto
     
  18. I need to sort something out, and it's probably the crank pressure that needs lowering. It already has a STM breather but not sure if it's with/without reed valve. But there's some oil around it aswell, also had some in the airbox.
     
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