XB pressurizing the oil tank, help

[UMDterp13]

Alright, got a cheap ass xb12r 2005. Knew it had issue but not this.

Who has experience or info on what to do when XB starts pressurizing the oil tank.
aka start & run it few minutes, uncap oil to check it but when you break it loose air blows out.

Already checked rockers, breathers. Google ect.

Line blockage would likely result in no oil pressure & it's pressurizing the tank so I assume return line is clear.


I'm open to suggestions:


someone can have the bike for $2500 also. It doesn't look bad. It hasn't been wrecked. I cleaned it pretty good, got some of the oil and grime off. I bought the bike for parts but it's clean title & rather keep it complete.

29k R tail w/ S front, stock minus bar conversion

 

[UMDterp13]

Took swing arm to case vent line loose, no oil coming out. Blow air into motor, slowly hisses back out.
Blow air into it swing arm direction, oil gushed back out.

Gonna run it tomorrow to see if that was the issue.

I'm gonna assume it was clogged vent from swing arm for now

 

[ToneTheMoan]

Good luck! let us know the result, i like to learn this stuff for my bike further down the line!

 

[Red93stang]

Wish this forum had email notification! Im interested to see what you find as well. So do you think its a oil blockage problem since the breathers are free?

 

[UMDterp13]

before work; I took air box apart again. clamped the breather in tight to the valve covers and blew in breathers reverse with 100psi. (swing arm vent line open at motor, upper most line on can cover 03-05)
* Front blew out, no resistance
* Rear At first no air even went into the motor, then got some nasty white liquid out after couple tries, blew much as I could out. But I don't believe this would block everything up. I believe air is escaping path of least resistance.

Battery was dead so I could not attempt starting yet, jump box was far away from the "shop area". Have to wait. If this bike is now fixed, I'm going to be shocked.

Will update you guys here. this is not posted on FB

 

[ToneTheMoan]

Its a good start to at least find something, here`s hoping for you!

 

[Jessman78]

Last year at the Dragon VII event when we stopped to get gas a guy with us had gas spray all over him when he opened the cap Not sure what he figured out but his name is cb750 (I think) on the forum

 

[UMDterp13]

Gas & oil tanks are separate systems.

Thanks tho

 

[Jessman78]

Sorry man, guess I can't read[confused]

 

[UMDterp13]

I'm an idiot.

blew air into the vent towards swing arm and oil gushed out"

That was with cap on. With cap off the air can be heard bubbling out... essentially that's an obvious hydraulic action meaning vent tube in swing arm is below the oil level.


****so what I found. Broken vent tube insert inside the swing arm. It's about 7" tall and screws into the swing arm. ****

It broke at the base causing it to be under the oil level, this means air cannot escape the swing arm so it builds when running (heat expansion)
That forces more oil into the motor sump & makes the bike work harder, I can only assume this would cause the engine to fail eventually due to oil pump stress.

 

[theMelvster6]

It's basically acting as of you overfilled the oil tank. It's not venting into the cam chest therefore not able to relieve pressure through the pcv system.

 

[Red93stang]

[up] Glad you found it!

 

[ToneTheMoan]

Well done good to know you sussed it out! columbo eat your heart out!