Oil Leak, Have question

4 replies to this topic
  • YZPaGuy

Posted June 12, 2013 - 10:27 AM


I have an oil leak from the seal behind the front sprocket. I just put a new front sprocket on at the beginning of this year. I noticed the nut that holds the sprocket on was loose when I disassembled it. The lock washer was holding it in place but it was loose. I torqued it to spec when I installed the front sprocket.

My question; Do you guys that work on these often use the torque spec or are you tightening the nut more? I am thinking that the nut being "loose" allowed the sprocket to vibrate some and cause the seal to go bad. The seal is original on an 08 so it could have also been just normal wear but when I took it off in the spring time to install the new front sprocket I had to use an impact gun to loosen the nut.

Thanks in advance for any input!

  • Bigdong

Posted June 12, 2013 - 10:59 AM


I dont torque mine to spec, just tighten and then put on washer. Job done.

Chances are your seals just gone bad, its not a big job.

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  • grayracer513

Posted June 12, 2013 - 11:31 AM


To begin, simply having the nut loose will directly cause an oil leak. This comes from the system oil pressure pushing the seal collar out far enough to expose the notches at the inboard end to the seal lip, letting the oil bypass the seal.

I almost always use an air impact to tighten the nut, and just go by the feel that comes with experience. Rule of thumb is that a quarter turn tighter than just snug is usually about right, but the specified torque should be adequate, too.

  • YZPaGuy

Posted June 12, 2013 - 01:54 PM


Thanks guys. I have it all apart and figured it was due to the nut being loose. Local ship had the seal in stock so I am going to fix it tonight.

It did leak a bunch of oil. The was still oil coming out when I stopped riding it. I dumped a quart in so I could start it and confirm it was that seal. Started right up and sounded good so hopefully no motor damage.

  • YZPaGuy

Posted June 13, 2013 - 09:50 AM


Put it all back together and all is fine! Thanks for the help. When I drained the oil there was allot that came out. I think I only lost a quarter of a quart. I got lucky I stopped riding when I did. Could have been allot worse!

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