Text only | Text with Images

Motorcycle Racing Forum

Motorcycle Racing => Wrenching => Topic started by: Kdiddy on July 09, 2005, 02:29:41 PM

Title: Presure in the crankcase?
Post by: Kdiddy on July 09, 2005, 02:29:41 PM
Last week I was riding and I fuelup.  My bike failed to restart.  I had just bought it so I just check a few things.  The air filter was really dirty, so I replaced it and the bike runs fine.  I took the oil fill cap off to check for fuel (Flooded) and it started to hiss.  I do not think there should be pressure there?  So I went looking for a crankcase vent hose.  Usually in the air box wrong, looks like after market tinkering(black tape on a hole in the air box.  I tryed to find the vent but no luck can any one help.  I have a 2001 gsxr750.  Thanks
Title: Re: Presure in the crankcase?
Post by: Super Dave on July 10, 2005, 04:59:49 PM
Doesn't sound right.  

Breather should be relatively obvious.  You'll need to pull the tank up.

Should be on the transmission side of the engine.  Maybe they routed the breather to either a separate filter or to the exhaust valving on top of the valve cover.
Title: Re: Presure in the crankcase?
Post by: Kdiddy on July 11, 2005, 10:14:38 AM
Upon further inspection I guess there is vacume not pressure in the crank case.  Is that suspose to be there
Title: Re: Presure in the crankcase?
Post by: Super Dave on July 11, 2005, 11:39:37 AM
The intake works on vacuum.

When it's not running...I don't know how it can have vacuum.
Title: Re: Presure in the crankcase?
Post by: Protein Filled on July 11, 2005, 12:56:26 PM
There can be a vacuum in the cranckcase if they did the "PAIR" mod, where they remove the PAIR valve and connect the crankcase vent to the hoses that the PAIR valve was connected. It's supposed to give you more horsepower, but not legal for the racetrack.

Title: Re: Presure in the crankcase?
Post by: Super Dave on July 11, 2005, 01:26:36 PM
That would happen only while running...
Title: Re: Presure in the crankcase?
Post by: Protein Filled on July 11, 2005, 01:29:24 PM
Pretty much, but it can stay pressurized for a couple of minutes after it stops running... Not sure how long after the bike was running did he try and remove the oil filler cap.
Title: Re: Presure in the crankcase?
Post by: Kdiddy on July 12, 2005, 08:30:06 AM
Thanks guys, I think it has been modified.  I have switches under the tail section that I don't know what it is for It goes into the wiring harness and advances my second set of thottle bodies.  The more I look the more nervious I get.  Thanks for the advice.

Title: Re: Presure in the crankcase?
Post by: Super Dave on July 12, 2005, 10:47:13 AM
Power Commander?
Title: Re: Presure in the crankcase?
Post by: Kdiddy on July 13, 2005, 06:18:00 AM
Thats wwhat I thought too but I does not go to the oewer commander or the ECM.  The wires run to the two or three diferent spot ahead of the computer.  The only thing i see it doing is making the motor that controls the throttle body butterflies move just a little bit.  I just leave it alone and try not to look at it.  
Text only | Text with Images