Amsoil 0w-40 vs Mobil 1 4t 10w-40 Motorcycle Oil?

[chico80x]

I'm having a hard time picking the right oil for my 05 Yamaha Grizzly 660 and I'd like to know if any of you can help me out. Right now I've narrowd my choices down to either Amsoil Powersports 0w-40 or Mobil 1 Racing 4t 10w-40. I'm pretty sure that either oil will serve my purpose well but was has me second guessing myself is that in the description that Mobil has on their website, they state that 4t is mainly designed with on road motorcylces in mind while the Amsoil is specifically designed for ATV's. Now my question is this, do any of you know if by any chance there are differances in the add packages of either oil that would make one better than the other? I also noticed that at 100c the Amsoil has a cSt of 14.7 vs 13.8 for the Mobil does this mean that at 100c the Amsoil is a little thicker?

I'll admit that I'm fairly new to all of the technical information on oil that most of you know but if I understand the viscosity chart here on BITOG correctly with a cSt of 13.8 the Mobil oil is a borderline SAE 40 almost a thick 30 weight?

Just some added information, this atv will be mostly used in Georgia on a hunting lease and will be used mainly for transportation but it will also be for some work. During the winter the coldest temp I plan on starting the atv in will be around 20F, it usually doesn't get colder than that where I hunt.

 

[daman]

I run Amsoil's MCV 20w50 in my Yamaha Warrior 350 air cooled, it seems to perform very well, and this thing runs hot(no oil cooler)always shifts good and smooth and no oil
consumption at all.

but yea you'll need a thinner formula for winter use i think
the Amsoil Powersports 0w-40 would be a pretty good choice.

one of the site dealers will be along and tell ya the diff.
for sure.i did notice at temp Amsoil's thicker then M1
if that matters to ya.

i've also had great luck with M1's MC oil..i don't think you
can go wrong with either, there about as good as it gets.

 

[pajim17057]

I run amsoil 0w40 in both of my honda atv's. It work great.

 

[Rickey]

Both oils have excellent reputations. Price and availability may make the difference.

I am biased in favor of the thicker Amsoil however.

Rickey.

 

[chico80x]

Thanks for all of your help and I decided to get a few quarts of M1 4T 10w-40 and run a UOA after 20 hours to see how everything is. What turned me off to Amsoils 0w-40 is that I have a feeling that oil will shear a lot more than the M1 just because of it's broad viscosity range.