Cure Your Leaky Engine.....honestly!

Discussion in 'Thumpers' started by laramie LC4, Mar 19, 2010.

  1. laramie LC4

    laramie LC4 flying something...

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    first a disclaimer: I AM NOT A PRO- THIS IS NOT MY PRODUCT!. i am just passing along info that was given to me by pro's and the creator of the krankvent. take this info as you will.....i don't need any grief for trying to help.


    Got Leaks?

    I have been plagued by a run of base gasket issues (REF) and while discussing a possible rebuild with an engine guru, he told me the secret to my problem. he also told me how to solve the issue. the great part is this will will work with ALL large displacement thumpers.

    first, the reason this happens;

    as the piston and crank rotate inside your case they create alternating pressure waves of positive and negative pressures. engine pulses if you will. as the piston comes down in the stroke you only have a finite area in which to maintain the air that was in that space prior. what happens is the excess pressure pushes the air out the crank breather tubes. this usually vents by one way or another into the airbox. now as the piston begins its travel back up the stroke a vacuum is created. now all that air that was just forced out gets sucked back in. THIS HAPPENS EVERY TIME THE ENGINE DOES A REVOLUTION! just imagine how many times this happens during a ride!

    this continued fluctuation between the positive and negative pressures puts an incredible strain on the seals and gaskets of the engine. the base gasket being one the biggest culprits. if you ride your bike aggressively, the problems are compounded even more.

    so how do we solve this issue ?????

    you remove the positive pressure and operate the engine in a vacuum. the krankvent allows the vent out, but not back in. if you know anything about hydrodynamics or any other science you know that things flow from high pressure to low pressure. if we operate our engine at a low pressure, there is no way the engine can leak. it's physically impossible.

    so how do we do this? there are a couple different models available to do this. one from THUMPER RACING and the one i purchased from ET PERFORMANCE. this is a good FAQ's sheet from ET. LINK.

    installation is very easy. you just need to find the vent line to your airbox, or an engine case vent line. if you have multiple vent lines, you will need to seal at least one of them off, or just vent after the 2 join. that's what i selected to do.

    here is the vent....

    [​IMG]

    it comes with small hose clamps and zip tyes.

    after much consideration, and recommendations for the inventor, i decided to install mine on the airbox side. i replaced the old vent line with some reinforced tubing from ace, then made sure everything was sealed up.

    sorry for the messy pics, my suspension is off to the tuners, but you get the idea....very simple.

    [​IMG]

    so far when running the bike has not leaked a drop. i still get some small amounts of residual leaking when the bike sits, but its nothing compared to how bad it used to look after a ride.

    ChrisC asked in another post about the dreaded "oil in the airbox" venting that happens to many of us. i'm not sure about that. i suppose that if you over filled your oil bad enough that it might spit out on the first few revolutions. after that i'm not sure if it will be able to vent out? good question. maybe i will call the man back and ask. if it did vent, i would probably pull the krankvent and clean it out, just to make sure that its able to seal.

    well that completes another lesson, go forth and maintain!

    laters,

    laramie :beer
    #1
  2. Pole

    Pole Adventurer

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    Superb write-up Laramie :clap
    I hope this will cure my blowing LC4 Adv. '05 cyl. base gasket.
    You wouldn't know what's the stock breather pipe diameter by any chance?
    ET-Performance site gives the choice of 2 x hose barb sizes: 9.5mm & 12.7mm ( 3/8" & 1/2" ).
    Thank you in advance.
    #2
  3. tdreyer

    tdreyer KTiM

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    Ah! Thanks LaramieLC4. You had eluded to a leak fix in some other thread and I was wondering.........:ear Definitely want to hear the size you chose.

    Don't suppose it'll help with the silly rocker cover leak?

    My SMC will hit 40,000 about the time I get to the end of the parking lot when I leave work today and I am starting to develop a few leaks myself.

    Who, pray tell, is the engine guru you have been talking with? That day will be coming for me sometime late spring early summer. When you have yours done what if any mods do you plan for?
    #3
  4. laramie LC4

    laramie LC4 flying something...

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    i purchased the 3/8 barb.

    and yes, it should help eliminate the leaky rocker cover (at least while riding).

    the benefits of doing this are many. not only the leak issues, but also less oil consumption, less blow by at the rings, and it will free up horse power. win-win in my book.

    laramie :beer
    #4
  5. TaZ9

    TaZ9 Been here awhile

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    Sounds like a one-direction valve similar to an automobile Positive Crankcase Ventilation (PCV) valve that is used to control engine emissions by recirculating the engine vapors and pressure, with the difference this valve is situated to just exhaust into the atmosphere, instead of back into the engine. The $75.00 price is a total rip-off (as all motorcycle parts tend to be), where a simple $3.00 PVC valve could be used to do the same function. Would be pretty simple to do and have the same effect.

    Ride safe!
    #5
  6. laramie LC4

    laramie LC4 flying something...

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    yes you are correct in that it is "similar" to the PCV valve. but if you would read, thats about where it stops. but if you dont believe me spend the $3 on the auto version and see how long it lasts and if it will even maintain the vacuum. :stupid


    laramie :beer
    #6
  7. rob748

    rob748 resident alien !!!!

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    l think some suzuki teams in the AMA superbike got bollocked for doing this on the 1000's in 08 ?
    they stated the same type reason but l think they did say it would add a small amount HP
    or l could be talking shit ( done that before, l am a internet mechanic :evil )
    #7
  8. tdreyer

    tdreyer KTiM

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    LaramieLC4, have you had a chance to try it out yet...:huhnever mind your suspension is out being set up. Hopefully I'll have mine next week and can report back.

    Anyone else tried this out yet?
    #8
  9. laramie LC4

    laramie LC4 flying something...

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    yes, i have rode with it on the bike multiple times now and it really seems to be working.

    laramie :beer
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  10. baloneyskin daddy

    baloneyskin daddy bikaholic Super Supporter

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    If the engine is running in a vacuum why won't it now suck the same gaskets inward?
    #10
  11. laramie LC4

    laramie LC4 flying something...

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    its not that high of a vacuum. i was worried about that to. i'd rather have oil coming out, then dirt getting sucked in.

    the only thing that this device changes is that the positive pressure no longer happens. the engine always ran at this vacuum for that very short time during every revolution of the engine. all we do is is make it so that the pressure stays low instead of bouncing back and forth.

    laramie :beer
    #11
  12. GSteve

    GSteve Long timer

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    Laramie, thanks for taking the time to post the photos and decription. Much appreciated.
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  13. cyclewizard

    cyclewizard Long timer

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    Someone always has to throw a monkey wrench into the equation. :lol3
    #13
  14. DirtyDog

    DirtyDog Omnia mea mecum porto Supporter

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    Funny. Take a proven $10 KLR pcv mod and tack on an additional $65 to make it work for a KTM.

    <object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/7GVXwhr1QoE&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/7GVXwhr1QoE&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
    #14
  15. handirifle

    handirifle Been here awhile

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    This is a cool thread. Might have to look into a mod like this on my XL600, if it doesn't already have one.
    #15
  16. Brendan J

    Brendan J Pfft

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    Why dont you plumm the other end of the hose into the exhaust header near the head and gain some extra vacuum effect on the crankcase. I have seen this done before and works quite effectively.
    #16
  17. MODNROD

    MODNROD Pawn of Petty Tyrants

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    I agree man, but......

    Not being silly, or defending the name of KTM (leaky, rattly, vibey, bloody.....:rofl ), but first thought of a simple PCV, but didn't think it would work with lots of compression and revs. Again, not having a go at KLR's (raced Kwaka's for years), but my 640 spins to 8000 with 12.1:1 comp and runs 12's. As well, the Japanese know how to make something basically oil-tight, as opposed to the Austrians it would seem.

    Have you used the PCV on something with a fair bit of grunt? :dunno I need something, cheap and effective I reckon is best, since I'm selling the bike, but don't want to pass on the bike to anyone until it's at least oil-tight. Rather lose the $100AUST up front than have to give someone my oil tray as part of the deal! :lol2
    #17
  18. laramie LC4

    laramie LC4 flying something...

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    there are 2 exhaust vents for the LC4, 1 at the rocker cover, the other at the base of the clutch. in order to vacuum seal the entire engine, i capped it at the airbox which allows both vents to still be attached. if not i would have had to plug/cap the valve cover and other inlet into the backbone. another reason is the designer told me to keep it as far from the engine as possible to prevent any "oil misting" that may get in the valve and cause it to not maintain vacuum. no big deal if it does, you just take it out and wash it with soap and water, but still its work. he said that if at all possible to put it on the airbox, and that's what turned out to be the easiest.

    laramie :beer
    #18
  19. ChrisC

    ChrisC Amal sex?

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    Laramie, so does it simply mount in-line to the airbox inlet or does it run to atmosphere with the airbox barb plugged off? :ear
    #19
  20. laramie LC4

    laramie LC4 flying something...

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    in-line and into the airbox.

    one thing that the designer mentioned (and its mentioned in the FAQ page) is that extreme dust can cause the valve to not seal. when i asked about, obviously concerned for the type of riding i do, he said as long as you vent into the airbox it shouldn't be any issue. he was referring to big twins venting directly to atmosphere. even if it does get dusty though, you can always take it out, clean with soap and water, then stick it back in. might be a good idea anyways as part of periodic maintenance. in theory, nothing should ever get sucked in, but im sure that just dust flying around will eventually end up working its way in over time.

    laramie :beer
    #20