crankcase pressure?


6 replies to this topic
  • brazen red

Posted January 17, 2008 - 10:26 AM

#1

I have just rebuilt my 1998 wr400 to replace a worn selector fork, which seems to have solved the problem I had with the bike jumping out of 5th gear.

Now on the not-so-good side.

I now seem to have very high pressure in the crankcase, enough to spray oil out of the channel that links the generator (rotor) area with the gearbox, and coats the rotor and stator with oil. Its as if the oil isn't being picked up properly, or maybe if the oil runs through one of the gearbox shafts - do I have to align the oil feed hole in this with something? This was the one thing that I wasn't certain about when I rebuilt the gearbox.... would this cause the problem?

I can't find any crankcase breathers that could be blocked so I assume the bottom end vents up the channel for the timing chain, and then out the top camshaft cover and the thick black pipe on the top (which is clear).

Any ideas most welcome, thank you.

Cheers, Red.

  • SXP

Posted January 17, 2008 - 11:28 AM

#2

I have just rebuilt my 1998 wr400 to replace a worn selector fork, which seems to have solved the problem I had with the bike jumping out of 5th gear.

Now on the not-so-good side.

I now seem to have very high pressure in the crankcase, enough to spray oil out of the channel that links the generator (rotor) area with the gearbox, and coats the rotor and stator with oil. Its as if the oil isn't being picked up properly, or maybe if the oil runs through one of the gearbox shafts - do I have to align the oil feed hole in this with something? This was the one thing that I wasn't certain about when I rebuilt the gearbox.... would this cause the problem?

I can't find any crankcase breathers that could be blocked so I assume the bottom end vents up the channel for the timing chain, and then out the top camshaft cover and the thick black pipe on the top (which is clear).

Any ideas most welcome, thank you.


Cheers, Red.


Sounds completely normal to me. The stator/rotor is always bathed in oil - this is the way the bike is designed. Ever take the left side cover off without first draining the oil? You'll have a mess on your hands - oil lives in those parts. So, unless I'm misunderstanding what you are trying to say, I don't think you have anything to worry about.

  • Birdy426

Posted January 17, 2008 - 12:26 PM

#3

Sounds completely normal to me. The stator/rotor is always bathed in oil - this is the way the bike is designed. Ever take the left side cover off without first draining the oil? You'll have a mess on your hands - oil lives in those parts. So, unless I'm misunderstanding what you are trying to say, I don't think you have anything to worry about.


...what he said...

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  • brazen red

Posted January 17, 2008 - 02:10 PM

#4

There is so much oil in here its gonna cause problems.

I've run bikes with the rotor casing off before and it didn't shower everything within 3 ft with a mist of oil under pressure. This part of the engine is linked to the gearbox to allow oil that has splashed off the cam chain to be collected and recycled. This isn't right I'm sure of it...there is so much oil in there....

Also, I've looked at many rotors on bikes before with this casing off and , yes there is a bit of oil around, but the rotor has always been virtually dry - not swimmin in it...

Thanks for your comments, but it wasn't doing this before I stripped it down - so somethings gone back together wrongly.... :cool:

  • SXP

Posted January 17, 2008 - 02:15 PM

#5

- not swimmin in it...


Definitely not swimming in the oil, but if you take the cover off without first draining the oil, with the bike upright oil does drain out from the open case and make a mess.

  • brazen red

Posted January 17, 2008 - 02:20 PM

#6

It really is swimming in the oil.

If I take the cover off without first draining the oil, with the bike upright oil does drain out from the open case and make a mess... but it didn't before !!

I discovered this problem by noticing oil coming through the gasket and out onto the floor in quantity - literally filling up this casing with oil.

  • SXP

Posted January 17, 2008 - 02:28 PM

#7

... but it didn't before !!



Both my 99's spill oil out the case without the left cover on. I've rebuilt both bikes and have been in and out of the left side for one reason or the other a number of times over the years, and if I forget to first drain the oil I end up with a mess on my hands.

Don't know what to tell you....

Good luck and let us know what you find.




 
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