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!