Ok, so here is the question what is the absolute best oil for a 400ex?

thanks

 

U just threw gas on a lit flame.....

Amsoil 0w40 hands down.

 

Crisco vegetable oil.Just kidding,your probably going to get alot of different answers.good luck

 

I did that once!

 

Maxima Extra oil

 

Some years ago it occured to me that I knew nothing about oils. This was a bit of an embarasment to me, seeing I am a biochemist........so I undertook a study of oils.........

After doing a lot of research, the conclusion I reached is that the synthetic oils have advantages over the petroleum oils, and the ester based synthetics have advantages over the other two types of synthetics. My choice has been Maxima Extra now for quite a few years, but Klotz and Motul also have ester synthetic oils.

Whatever oil you choose (petroleum or synthetic), you won't go far wrong as long as it is motorcycle specific API SG/JASO MA! (Note that there are no "car" or "diesel" oils that are API SG or JASO MA!)

Some good reading: http://www.thumperfaq.com/oil.htm

Some info on synthetics. Just for the record, Rotella is group III, Mobil 1 and Amsoil are group IV, and the esters are group V: http://www.maximausa.com/technical/l...beNews2002.pdf

 

Unfortunately, Maxima doesn't make Extra in anything lighter than 10W40, which would make a great summer oil for you. In the winter however, you need to run 5W30 or maybe even 0W30 if it is extremely cold (my mother lived in Calgary, and she has told me stories about how cold it can get!). Maxima does make a 0W30 in their Ultra line (Ultra is Extra with the addition of a very special ester that makes things very "slick". It is rated MA, so it still shouldn't make your clutch slip. Personally, I prefer to run Extra for recreational riding, and would run Ultra only if I were racing.)

http://www.maximausa.com/