I changed the oil in my 2000 Yamaha Big Bear 400 4x4 to Amsoil's 0W-40 synthetic ATV motor oil. I don't know if it's going to help my engine at all. It did however make my transmission noticeably easier to shift. Just figured I'd pass that along. YMMV!

 

We have been going back and forth about synthetic in the Honda forum: http://forums.atvconnection.co...tid/8/threadid/561263


I am however a little confused! Does this have a manual trans, or a belt drive??? If belt, how is the engine oil going to effect the (nonexistent) transmision? Or, are you refering to shifting the transfer case????

 

It has a 5 speed manual transmission with a semi auto clutch. The engine and transmission are one unit and use the same oil. It seems to turn over a little quicker in the colder weather too. It definitely shifts easier though.

 

I am no big fan of PAO based oils (unless they are blended with lots of ester), but any synthetics will be thinner when cold than a petroleum oil of the same nominal weight.

And being 0W40, it should have somewhat less parasitic fluid drag than a 10W40 for example, so you might see a little increase in performance.