Just bought a 00 WR 400 and have been looking at all the posts about Mobil 1 oil. Many of the links were no good anymore but I found a good one. http://www.mobil1.com/motorcycle/index.jsp In a nutshell Mobil does not recommend using that oil in your bike. They produce motorcycle specific oils. Obviously many people have and are still using it without problems but for what it is worth they do not recomend it anymore.