I'ts time to change the fork oil in my 06 yz 450 but I am not sure what to use. I would like to replace it with the same oil it came stock with, but I don't know if it is yamaha O1 or something new for the SSS forks. Any one know what weight yam. O1 oil is? Which oil do you guys use? Also, do KYB forks still have a problem with the mid valve shim fatigue causing the forks to feel soft after a period of time?