This should answer the question in detail. Found info on some web site:

Motorcycle engines possess inherently different mechanical characteristics than those of automobiles. Thus, these characteristics require inherently different oils to provide for maximum performance and long life. Though 4-cycle motorcycle engines may be considered more similar to automobile engines than 2-stroke motorcycle engines, they still have very different performance requirements. Historically, 4-stroke motorcycles have had problems with gear pitting wear in the transmissions and clutch slippage. In many cases, this can be directly attributed to the oil used. Most automotive engine oil is developed to minimize friction and maximize fuel economy. Since the oil for many 4-stroke motorcycles is circulated not only through the engine (as with an automobile), but also through the transmission and clutch, different characteristics are required of the oil. First, a certain amount of friction is necessary to prevent clutch slippage. Second, the oil needs to prevent wear and pitting in the gears of the transmission. These and other essential characteristics are addressed in the standards developed by Japanese Automotive Standards Organization (JASO) for 4-stroke engines.
As with the 2-stroke classification, the JASO 4-stroke classification is also divided into grades, MA and MB. MB is lower friction oil, while MA is relatively higher friction oil. Other than friction, the JASO 4-stroke classification tests for five other physicochemical properties: sulfated ash, evaporative loss, foaming tendency, shear stability, and high temperature high shear viscosity (HTHS). Sulfated ash can cause pre-ignition if the oil is present in the combustion chamber. It can also contribute to deposits above the piston rings and subsequent valve leakage. Evaporative loss and foaming reduce the amount of lubrication and protection in the transmission, engine, and clutch. With less shear stability, oil loses its capability of retaining original viscosity resulting in increased metal-to-metal contact and wear. High temperature high shear viscosity tests provide viscosity characteristics and data under severe temperature and shear environments.

 

It's hard to believe the rumors of clutch slip are still out there and being posted by the majority. I guess people have to qualify paying an extra $4 a quart... LOL!

Wanna know the real difference between ATV oil and car oil? The picture on the front of the bottle.

Just don't by Energy Conserving oils (or ECII, even worse) and you'll be fine. Most if not all 10w40 weight oils are not EC oils. But most 5w30 is.

M1 15w50 is not EC, and a great oil to use in warmer temps. I use Shell Rotella T 5w40 in my quads (rinny and z).

 

ummm...no. Mobil1 15W50 is good, but it is not the best for a motorcycle. Take a look at SAE's website and search their archives for their comparison on motorcycle oils. Amsoil is the best motorcycle oil on the market. Mobil1 motorcycle specific oil was pretty good too, but the red cap 15w50 was nowhere near the best. Just some trivia for you automobile oil users.

 

I dont know, everyone is going on this fully synethtic thing and I'm going to try it. I know that Mobile 1 makes fully synthetic oils for both two-stroke and four-stroke engines. All I hear is good things about fully synthetic oils so thats the way I'm headed. But if you do get the fully synethic oils make sure its for motorcycle use and no the one made for cars and trucks. I dont know what kind of quad you got but if its not a high performance quad then I wouldnt worry about using a motor oil, but if you got something with an manual clutch then I would stay away from it. I've used motor oil in my 250x when I had that and I had no problems, but now that I got a raptor I'll spend the extra money just for the piece of mind. Just my opinion though.

 

I use to use Mobil 1 Sythetic 0W-40 oil formulated for European cars in my scram just because it was more redily available. Now I have switched to Amsoil cuz I have found a dealer and personally believe that Amsoil is the best oil out there

 

Do not use "Energy Saving" (like noted above with FM) car engine oils in your atv,
they WILL cause the clutch to slip. Standard automotive oils will not, but they are not
formulated for the higher rpms of motorcycle engines and WILL foam up on you, unless
you have a lower rpm engine, like Honda's longitudinal ute engine.

 

Got a direct link? Interested to see if Rotella=T synth was in there or not, and who performed the tests. Amsoil is good oil, but I don't buy it simply because the company itself is a little shady... amway oil! LOL!

Anyhow, even if one oil is "better" as rated by SAE, M1 and most other synth oils are so good that it's like reaching the moon with a step-stool as for the difference.

I never said M1 was the best, I said it was great... millions of motorcyclists can't be wrong, and they spin and much higher RPMs than any quad does.

I have even used M1 5w30 in a 1986 250R (it is EC oil) with it's original clutch and had no slipping. I just get so sick of hearing people regurgitate false claims marketing they hear from their steeler (or from someone on a message board) to convince them to buy Honda/Polaris/Yami oil only, paying through the nose for a product just with the name on it. Talk about blind faith.. they'll believe them when they say auto oil is bad, but when they bring a quad into the same people to do the "1st service" and charge them $200 for adjusting cables, changing the oil, and "checking the valves" it makes me shake my head.

 

I ran Castrol 10w40 (automobile oil) in my Ozark and it worked perfectly well, till>
last summer when it got hot and I was riding hard, it started SMOKING! This was a brand new atv and was only a few months old. I have switched to motorcycle oil and have not had a problem since. Those of you who think Mobil 1 red cap is good oil are right............if you use it in your car! It is NOT motorcycle oil, GET A CLUE! Mobil 1 makes motorcycle oil its called MX4T. With that known, why would you keep using their CAR oil in your quad? DUH!

 

I've seen a dozen different "tests" and have read dozens of posts here in the past couple of years.

The clutch slippage problem DOES NOT relate to manual clutch sportquads!!

The clutch that commonly does slip using automotive oil is the centrifugal clutch shoes on the end of the crankshaft on an auto clutch quad. These clutches are designed to slip for smooth engagement. It doesn't take much to get more "slippage" than you want.....if you know what I mean.

I know guys who have ran automotive oil in their BigReds and TRX300s for years and have never had a problem...........but I also know those who have.

It's the owner's decision and risk.

 

As a motorcycle tech during a period when mutli-cylinder, small bore, high reving engines
were fairly new, I have seen first hand the damage standard (notice I say STANDARD)
petroleum-based auto oils can do. I even saw a guy who put Teflon oil treatment is his 4-cylinder Honda
750 and blew it to h*ll. 3 month old bike, totally ruined. And no warranty would cover it, so he brought
it to us (a KawiSuki dealer) to see if we would fix it. We told him we would make him a good deal on
any bike on the lot, but repairs were impossible.

KNOWSALOT is correct. The clutch slipping problem is with centrifugal clutches not manual clutches.
And it is only due to FM oils.

bvstone, I agree with you on Amway. Wouldn't buy sh*t from them if they were the last turd dealers
on the planet.