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How to: Crankcase Vent Mod.

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#1 · (Edited)
How to: Crankcase Vent Mod. *Updated* flow test pg.6

This Crankcase Vent Mod. will use the vacuum supplied by the exhaust through the reeds to create a negative pressure in the Crankcase.
This helps the internal parts do their “work” without the resistance of positive pressure.

The engine is more efficient with the pressure drop.

This mod. should help your engine rev. faster. HP gains? Depends on flow. I have not "yet" measured cfm on the 10.

How the Air Switching Valve works. I cut this out of the 08 service manual and inserted some text. May be useful to help understand what happens here.



1/2" T and 1/2" I.D. 5/8" O.D. hose replaces the stock components. Our vacuum supply.



This pic. is a screen shot of the crankcase vent line (highlighted in Green) from the service manual. This is the crankcase vent hose.



Here you can see an inside view of where the crankcase is vented to in the 08 airbox. Does the crankcase have positive pressure? Notice the small amount of oil circled in black.



Here you have your vent line disconnected from the airbox (circled) and the new line fits right inside. Reuse the same pinch clamp.



Airbox nipple gets a 1/2 - 5/8" I.D. cap and can be returned to the stock setup easily.



I routed the new vacuum line on the right side to avoid the already cramped fuel line on the left side.



Obviously, connect the vacuum line to the 1/2" T



When the mod. is complete it looks something like this.



I used about 3ft. of hose, one 1/2" Tee, two 5/8" caps (I think 1/2" caps would work) and 6 stainless hose clamps. Cost around $5.

Flowtest vid. on page 6
 
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#137 ·
It looks like the pictures have been deleted because on Photobucket so I'll re-post some of them. I have since made this mode to my gen 3 and run it a number of times and there is 0, none, nada in the catch tank, it may have a few drops of water.
If your engine is puking oil and you do not want split the case to do this, sharpen a steel rod that will fit into the breater outlet and drive it through the plate, it works.
There are 2 exit ports from the breather cavity, 1 exits behind the flywheel and the other is actually be low the normal oil level in bottom of the pan.
 

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#138 ·
This is the baffle system that I have developed for using the gen 3 engine in our race car. The baffle prevents loss of oil pressure in cornering and braking. In a car since the engine does not lean in the corners the oil pickup can easily be exposed and subsequent loss of oil pressure. This can happen in cornering and on acceleration after a heavy braking event.
The baffle 0.062 thick 6061 aluminum and is sealed on both sides with the Kawasaki black RTV no pan gasket.
 

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#139 · (Edited)
i dont run this mod on street engines, but all strip motors. best to use large 3/4 stiff auto hose so as not to collapse. larger engines respond better than 1k's. built hayabusa engines respond best, usually around 3 hp measured after sucker mod capped for tuning then plugged into crankcase for final
hp pull. will change exhaust note. have it on my gen 2 10 strip bike but unmeasured on dyno as i did it later. made a difference, bike ran best et/mph next time out after mod and still runs this way. just took a 08 hayabusa off the dyno at 221 hp, supposed to be street ridden and strip. because street originally left this mod off, decided strip only bike. we removed 10 lbs from rear footpegs, rotor, and caliper and did this mod.my et calculator said .08 quicker 10 lbs gone, estimated + 3 hp gained. exactley how much faster he ran consistientley this weekend. just one of the tweaks u try getting all u can, cost $10.
 
#141 · (Edited)
no good explanation why not to, just have never done it on street engines, probabley because it does tend to flatten exhaust note which some question. soon as we hooked this mod up busa owner said ex sounded different as i had told him it may, first timeslip got him over that. vent all street engines to atmosphere/cap airbox. does it make a difference on strip? my results positive, should do same on street. simple mod, home depot has the tee and straight coupling, parts store has the hose.
 
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