What is the difernece between Mototcycle Oil and Automotive Oil?

Question

I have a 1996 Yamaha Kodiak ATV with a "wet clutch". The dealer (salesman) says I must use motorcycle oil. However the manual says that I should use "Yamalube 4 (20W40)" or "SAE 20W40" type "SE". I know the current API standard is SM.

What is in Motorcycle OIL to make it speial. Can I use SAE 20W40 type SM with out harming the "wet clutch"?

Thanks for the help

I understand that lot's of people say that the motorcycle oil has better friction properties for the wet clutch.

Also I see that Amsoil and Castrol talk about the benefits of their oil in a wet clutch application. http://www.amsoil.com/lit/g2156.pdf

I have searched the API site and don't get any info on "wet clutch" or Motorcycle oil. Howeer they do mention JASO. But just mention.

I see the article from Motorcycle Consumer News is from 1994 and I know that there have been many changes to motor oils simce then. It also only adresses the viscosity issues not the friction issues. Friction midifiers have been added in lubricants

I don't want to comeoff agrumentative but does anyone have a link to some independant testing against standatd oil?

I am starting to believe I need something other than "good old dyno-juice" of some API service rating. But how do I know what I do need? Other than going to the 'stealer'

Thanks for the help

Answer 1

The 10w30 car oil with moly will make your clutch slip. Most other stuff will be fine. I use shell rotella 5w40 $18/gallon from walmart, and I have nothing but good things to say about it.

I've linked to a study on automotive oils vs. motorcycle oils below, and they found that in most cases the car oil was superior in all respects.

Answer 2

Motorcycle specific oils contain additives banned by the EPA. These oils are made overseas which accounts for some of the price difference. The additives were mostly to carry off heat. I ride a liquid-cooled flat six engine mc. I have used mostly Mobil 1 (gold cap) auto oil for the best part of 148,000 miles. Heavier weight auto oils do not contain the friction modifiers that would cause clutch slippage. 10w40 and heavier should be OK ... * as long as the bottle does not carry the words Energy Saving in the sae circle on the back of the bottle. Having made a short story long, the answer is "no". :-)

Answer 3

Hi there !
A couple of comments on this
Ref transmission sharing the engine oil - Can I introduce the Austin Mini ? 1959 to 2001 (approx) Always used standard engine oil and never (to my knowledge) suffered as a result.
Ref high temperatures - Many cars use turbo's now and their bearings run very hot.
I believe the worst job the oil has to cope with in an engine is the Cam lobe to follower and that's common to bikes and cars.
I notice several mentions of synthetic V's Petroleum based oils - I think Synthetic is the same stuff but broken down and rebuilt so to speak. (Castrol used to use a vegetable base - Castor in fact, but I doubt they still do)
The only valid argument I see here is that some of the modern oils have friction reducers which wet clutches don't like. Avoid these and your OK
So will an oil that runs 6000 miles in a turbocharged multi valve car engine run 1 or 2 k in a bike - probably yes !

Answer 4

Motorcycle engines use oil for the engine AND transmission, and there is no separate transmission fluid for the gears like a car has.

Many nasty acids and chemical byproducts are produced during combustion, and the oil absorbs it. That's why you change the oil in your car more often than the tranny.

But in a motorcycle, all those acids are eating away at your entire engine since the oil is all you get. Motorcycle oil contains MUCH more acid neutralizers and friction modifiers (so your clutch hooks up) than car oil does, and unless you want to corrode your entire transmission I'd go with motorcycle oil.

Shakespeare's link only talks about VISCOSITY, which of course will be identical between car and motorcycle oils. There is no mention of combustion byproducts or acid neutralizers at all.

Answer 5

Oh no, its the dreaded car oil vs motorcycle oil question again. You want to know what the difference is...its about $3 a quart, thats the difference. Actually, it is a little more complicated than that, you could read the technical crap for the rest of your life. Just use a quality oil of the specified viscosity keep it at the proper level and change it frequently and you won't have any problems.

NEXT DAY EDIT: Let's look at it this way, your machine probably holds two quarts, so, whether your putting the most expensive synthetic in it or the cheapest dollar store crap it won't save you alot of money. Your machine won't know the difference, but, IF it gives you peace of mind put the expensive stuff in.

Answer 6

geo46er gave the correct answer.
If there are any nay-sayers out there, read this.
http://www.ducatimeccanica.com/oil.html
I hope everyone reads this all the way through, so we can put this debate to rest, once and for all.

Motorcycle Consumer News is an independent motorcycle product tester. They don't take kick-backs from companies for giving a good review. They don't allow advertisements in their monthly magazine for the same reason. They're the motorcycle equivalent of Consumer Reports.

Answer 7

You can use any engine oil as long as it doesn't say "fuel conserving" in the API circle on the back of the bottle. If it does, it contains teflon, which causes the clutch to slip.

Answer 8

Thank You Geo46er! Good Answer

p.s. Just don't use any full synthetics or your clutch Will slip..

Answer 9

you pretty much answered your question....some auto oils will make your clutch slip...but a really high quality super heavy duty oil is ,shell rotella...its used in heavy equipment and is really good esp.for air cooled bikes in hot weather...dosent break down easy.

Answer 10

bike oil is formulated with different things to withstand the higher heat bike engines will put it thru. if u put car oil in a bike, that engine will quickly push the oil into thermal breakdown....and basically have it for lunch.
in the manual for my sportster, it specifies that in an emergency situation if 20w50 mc oil isnt available, to use 20w50 oil that is rated for diesel engines.

i prefer to use what's called for in the manual when it comes to the primary especially.