2008 WR450F Oil in Air Filter Box?

4 replies to this topic
  • dustinsb

Posted July 11, 2016 - 10:45 PM


I have a street legal 2008 WR450F that runs great but recently I noticed a small amount of oil in the air filter box under the seat. I recently rode the bike on the freeway for a short time where it has to run at high RPM in 5th gear to be able to pull 65MPH. Anyone have any idea what's with the motor oil in the airbox? I'm thinking it's probably time for a valve adjustment also if anyone can direct me to a thread for how to do that (I've done many but not on this bike). Thank you!

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  • William1

Posted July 12, 2016 - 04:43 AM


Not the valves.

It could be one (or all) of three things, none cause for alarm

Over oil air filter, dripped to the bottom of the air box - Wring it out better

High RPM blow by, pretty common with an engine run at or near peak rpm for an extended period of time. You could consider a final gearing change to drop rpm at speed. You have more than enough HP to drop the ratio by 20%

Over filled engine. Drain the oil, measure it, refil with the exact amount as stated in your manual.

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  • stevethe

Posted July 12, 2016 - 05:13 AM


Yup any more than a quart after a oil change and you have oil in the air box. It's very common.


If you want to adjust your valves use something like this https://www.google.c...=utf-8&oe=utf-8

  • Swes

Posted July 12, 2016 - 03:53 PM


+1 on the over fill comment . Dirtbikes didn't really have highway cruising in mind when they were designed . What oil are you using?

  • dustinsb

Posted July 13, 2016 - 10:15 AM


thanks for the replies! Yeah I must have put a hair too much oil in when I did the last oil change. Thank you!


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