Leaking Seal 08 YZ450F

I posted before I had a leaking countershaft seal on my 08 450F. I bought a new seal, collar and installed it. Started the bike all assembled and it started to leak again! It leaks as soon as the oil circulates. I have the seal in correctly, and driven it with a pvc pipe. Everything is right, I made sure twice. I don't know whats causing it to leak! Need some help, I am so frustrated with it right now. I have another new seal, I was thinking of removing the new one I just installed and just do it again! Need some help with this one! Thats how frustrating this is being. Thanks, any feedback will help im sure.

Besides the normal hazards of dislodging the lip spring, or cutting the lip, four possible errors come to mind:

  • Failure to replace an excessively worn seal collar
  • Failure to replace the seal collar/output shaft O-ring, or improperly installing or damaging it
  • Failure to install the seal square with the shaft (tilting the seal)
  • Seating the seal too deeply, allowing oil under seal lip via the collar cut-outs (seal should be about 1.5mm "proud" )

Did you replace the o-ring? Did you pack the inner lip of the seal with white lithium grease?

I replaced the collar,and the seal with oem yamaha parts, because the previous owner did not have the collar on the shaft.

Grey, the seal did tilt seat going in, maybe that is causing the leakage. Am I supposed to use a grease on the seal going in? I have another seal and Its my first try doing this.Thus, extra parts for my mess ups. Its frustrating to see it leak, I am thinking of doing it again, but I think I need a walkthru if anyone can help. Thanks!

Besides the normal hazards of dislodging the lip spring, or cutting the lip, four possible errors come to mind:

  • Failure to replace an excessively worn seal collar
  • Failure to replace the seal collar/output shaft O-ring, or improperly installing or damaging it
  • Failure to install the seal square with the shaft (tilting the seal)
  • Seating the seal too deeply, allowing oil under seal lip via the collar cut-outs (seal should be about 1.5mm "proud" )

I removed the seal and went for a second try using your advise. Seated the seal square and tapped it in with pvc and a mallet. Tried to keep it proud, very hard to do if you go too far you failed. Started the bike up and viola! Not leaking. Its my first seal, so Im "proud"

:lol: Thanks!!

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