drive spocket oil leak yz450f 03

:applause: hi all my yz leaking bad from the dive shaft i have changed the outer seal &the o ring & it still leaking , changed the oil & filter checked the oil pipes help!!!

Check the countershaft for scoring. Any scoring will allow oil by. It might pay to run some fine emery cloth or sand paper over the part of the shaft that contacts the seal. Just make sure you go in the direction of rotation. Make sure there isn't any debris where the seal fits in the cases and, while you're at it, change the rest of the seals. They are probably all the same age. It is a chore that should be done every 5 to 10 years or so.


i've put a new one on

countershaft seal

Sorry to drag this up again but I'm having this same problem. 2003 YZF450

It was leaking a lot out of behind the drive sprocket, so i pulled it and replaced the seal that was in behind there. I made a 40km trip and it is again leaking but not as bad. I've continued to drive it and it doesn't seem to have gotten any worse.

I recently bought the bike and it was clean of oil. I ran it in the mud and let it cake on, so I figured the mud wrecked the seal somehow.

When I replaced the seal there was some grass kinda half in the seal. There was also kind of a 'cover' that went over the seal. This cover had oil caked in it, but i thought maybe it could have been the remains of a paper type gasket...

Any advice on what my problem/cure could be? Thanks

In addition to the seal, examine the collar it runs on (#22 in the illustration). If there is a pronounced groove in it, enough say, to be felt distinctly with your fingernail, replace it. A grooved collar will prevent the seal from working correctly. There is also an O-ring (#23) that seals between the shaft and the collar. The metal cover is intended to baffle away most dirt and mud, and should be scraped as clean as possible.


Jeeze, that's awesome! I just finished putting on my trail tech kickstand that i learnt about on this board, now i get a reply in 8 minutes :applause:

That's the picture the guy at yamaha showed me...i bought the o-ring but i didnt put it in figuring that the seal would do the trick.

Im gonna bet that im gonna wreck my new seal taking it out again eh?

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