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MaxPower

Crankcase Venting

5 posts in this topic

I see the 05 WR (I have a 04) vents the crankcase into the airboot

Doesnt the added airpressure screw things up as far as jetting and such?

It comes from the factory like that and Yamaha is pretty smart. I just dont know if they did that for engine longevity or they did it for emission crap.

It looks like a clean set up and I wish to avoid a motor full of water again

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Hey if your happy with the way the bike is running just leave it alone.Most people do the mod along with fitting a pipe , jetting etc.

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maybe Im not wording it right Graazzy. Either that or Im not understanding you

I want to add the airboot from the 05 to hook my crank case vent into. I didnt do it yet

If I do that, will the air that is blown out of the crank case that will now be going into my intake alter the jetting or effect how my bike runs?And I see oil comes out of it at times.If I tip my bike over, wont I be filling my intake up with oil?That cant be good.

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will the air that is blown out of the crank case that will now be going into my intake alter the jetting or effect how my bike runs?And I see oil comes out of it at times.If I tip my bike over, wont I be filling my intake up with oil?That cant be good.

The Crankcase vent does not "Blow" it only vents the crankcase pressure from the positive and negative pressures caused by the underside of the piston. When the piston goes up to TDC the piston causes negative pressure in the crankcase or that volume of air (pulse) is sucked into the crank case vent. When the piston goes down that same volume of air (pulse) is pushed out the vent.

Many thread posters have used a Tee venting the tee into the air box and leaving the standard vent line in place to drip oil. the tee breaks the vacuum most commonly found (on the negative pulse) when trying to start the bike while the vent hose is under water or under sand at the crest of a dune.

Hope this helps:blah: :confused::excuseme:

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thank you G Cannon

That does help

I understand what you said

So does everyone with a 05 or newer WR that has the crank vented into the airboot get oil in their carb when the bike is tipped.I know the bike would have to really be on the side or almost upside down, but its not hard to get into a situation like that trying to climb a steep hill or wiping out in a gully.

Ive been there

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