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crankcase breathers

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  • crankcase breathers

    Does any body have an improved crankcase breather solution I am currently running a 6' hose 1/2" dia to the tail section with a KN filter and it still pumps oil when I run it on the dyno. I am thinking of a second breather added to the front valve cover any body tried this does it work. Does any one know what is inside the crank case on ther other side of the 3/4" hose connection that the breather tank attaches to, is there ia one way reed valve or something not having had an engine apart could someone enlighten me as the manual does not show any thing and I have just put a piece of 3/4" hose on that connection and when you blow on it it moves air but if you suck on it doesnt which leads me to beleave there is some kind of one way valve on it.
    Last edited by doug; 07-16-2003, 06:25 PM.

  • #2
    what I have done is very similar just in the tail I made a catch can out of 2 spray paint can lids. Made a hole on the top on just bigger than the hose Wraped the part of the hose that goes through the hole with part of a t-shirt and then taped the 2 lids together seems to hold up well you just need to drain it after every hard ride. question for you, what type of air box are you using If its hermits what or how did you seal the tubes to the box with?


    • #3


      Why not make sort of a "weir" put the crankcase side hose in the bottom, then a divider, then the breather hose out the top. Make the oil do a direction change or two and it won't be able to keep up with the air and will fall out. That is the basic idea. I could draw a picture or two, but hten I gotta scan 'em and stuff. The stocker works well on my TLR I get no oil in the airbox, why not just use that? Or if you have and S get the stuff for the breather from an R?


      • #4
        I am using a hermit dragon air box and tubes and I use the handy mans secret weapon, duct tape to seal the air tubes to the box the left air tube would not go all the way through the frame so I cut it short and it fits half way through and then seal it. I also use duct tape to seal the lid.


        • #5
          I have never had oil in my airbox either. Why do so many have this problem?

          My sig image busted the height and size limits.


          • #6
            There is a reed valve set-up on the breather Doug.u
            "I spent most of my money on Scotch, women and cigarettes. The rest I just wasted"


            • #7
              you probably have had oil in the air box and just not realize it. Next time you have the air filter off look down the throttle body with the throttle open and look at the back side of the intack valves you will find carbon deposits there this is from the oil being sucked into the intake through the breather in the air box, also if you pull the little sponge out of the air box corner and look in the bottom you will find oil. This happens after a high rpm run it is really bad news if you are running a race engine with high compression pistons as it will cause detonation, but more importantly it means the engine is trying to be a compressor and this costs horsepower, on a v max engine a good breather setup is worth 5 HP.


              • #8
                ahhhhh I see now.
                My sig image busted the height and size limits.


                • #9
                  Doug.... I will see if I can describe what I did for the last high comp motor....

                  if you look at the point where the stock breather hose comes out... there is a nipple that it mounts to. I cut the stock hose just a hair line above that. went to home depot and got a length of clear hose that the inner diameter was the same as the outer diameter of the stock hose (dont remember the exact diameter) mounted this hose over that and clamped it tight. Ran the hose up to the front of the bike, over the radiator and back down the other side of the motor. At that point I looped it down then up (to give a good low point in the hose) then finished it with a 90 degree elbow into a K&N filter.

                  So in essence I was using a larger diameter hose as the catch can. Never had any problems blowing oil after that.

                  Hope this helps. Cant take pics as the bike is down gearing up for the bigger motor.

                  Coming Soon!


                  • #10
                    Yep, it's funny how everybody is changing air filter, modifying airbox, porting heads, changing exhaust to get the top part of the piston to breath. But there is the downside of piston too, which has to 'breath' also. This is not so important with I4's, because when 1 cylinder is going up, other is going down.

                    I take no liability if someone burns up his/her TL with Jarkko/Sparkko/plus mod It's safe if it's done right....

                    Originally posted by tv1000s
                    "If i had a garage half the size of the smallest garage you guys had i would build a tl powered airplane with lazers"


                    • #11
                      I have a Hermit box also. What I did to seal it is use some aluminum tape it is fairly rigid and sticks well. I didn't bother to try to seal the tube to the box I sealed the box to the frame holes and then slid the tubes over the tape inside the holes and this seems to have sealed it very well. Don't try to make a continuous ring to seal the box, use small strips to bridge the gap between the box and the frame holes and try to ovelap them as much as possible. I have tested this at over 150 and all the seals held up I just use duct tabe over rubber plug bolts the same as for your wind screen to seal the lid to the base. This is what has worked for me. Now I need to perform the oil seperator mod to keep the oil off the side of the frame, looks like a great design.
                      "We can't stop HERE, this is bat country." HST
                      Dead Horse Racing Tucson, Arizona
                      " You can't beat a dead horse "