I have a 03 Rancher with over 5000 miles on it and have been running Castrol Syntec oil in it since after the break in. I just purchased a 03 300ex and wanted to change the oil and use Castrol Syntec. I called the dealer to see if I could change over and he said yes but not to use automobile oil, only use motor cycle oil. Is this true or a dealer trick. I have not had one bit of trouble with the Rancher shifting or anything else.

 

This is a common question. They say that regular oil shouldn't be used in ATV or motorcycles because the oil in an ATV lubricates the gears too. Because of the shearing action of the gears, regular oil breaks down faster. I believe it. Regular oil is made for pistons etc. where there is no shearing going on. It's just up & down. I use motorcycle oil in my ATV's. Sure, it's $5 a quart but since they only take a few quarts, why take a chance? I used to use regular oil and didn't have any problems but that doesn't necessarily mean I didn't do damage or shorten the life a little. That's just my 2 cents.

 

I have been using Valvoline 10wt-4 in all of my Honda thumpers for over 20 yrs and using it in my Chinese ATV's since they were new. Never had a oil related problem with any of them. My KTM gets Amsoil 10w40 motorcycle oil.

 

Years ago when I did hired hand farm work, there were a bunch of 3 wheelers there with thousands and thousands of abusive hours on them, running nothing but Rotilla 15W40 diesel oil...

That being said, one of the other differences, besides the same oil being used in the gears, is that many ATV's and motorcycles have a clutch that runs in a bath of oil. The oil would need to provide enough friction for the clutch to engage, and also keep wear material in suspension.

You could probably get a long life with most quality oils, but the recommended oil for your machine in normal temps would be a 10W40 with API specification SG or better that does NOT say energy conserving in the logo, and also meets JASO standard MA (motorcycle specific standard for wet clutch applications).

That doesn't necessarily have to come from the dealer. There are a variety of other oils out there in both dino and synthetic.

ReconRanger, a member here, knows a bunch about different oils. If he doesn't reply here, I'm sure he wouldn't mind giving you a better explanation and/or recommendation if you PM him.

 

<div class="FTQUOTE"><begin quote>Years ago when I did hired hand farm work, there were a bunch of 3 wheelers there with thousands and thousands of abusive hours on them, running nothing but Rotilla 15W40 diesel oil... </end quote></div>
I have used just that oil in everything that uses it.

The gear argument just dosen't cut it in my mind.
Used Rotella in the gear box of more than a half a dozen bikes and quads I have owned. Never a problem.
One was a GS1100 that put out more than 4 times the horse power of a quad.

One more thing, Rotella is not an energy conserving oil so it's fine for your clutch.

 

Yeah, using an oil with a CH or higher diesel rating is probably better than an automotive oil.

 

This is a great article on this very topic: http://www.thumperfaq.com/oil.htm


More good oil reading: http://www.sportrider.com/tech/146_0308_oil/index.html


The trouble with car and now the reformulated diesel oils, is that they have reduced levels of the high pressure/anti-wear additive of ZDDP, which is necessary to protect high pressure areas like the gears of your integrated transmission. This was mandated by the government because of catalytic converters. Your quads don't have cat converters, so why in the world would anybody want to run a downgraded oil that is not going to give you the best possible protection???

In addition, "car" oils will contain inorganic friction modifiers like moly, that can make your oil bathed wet clutch slip, so that is yet another reason to avoid them. (There is however now a new generation of organic friction modifiers, that are wet clutch safe...but you will only find them in the high priced premium synthetics like Redline or Maxima Ultra. These will net you a couple extra horsepower!)

Any motorcycle oil that is rated API SG/JASO MA, is going to be a good choice! The SG insures that it has pre-cat converter levels of ZDDP, and the MA insures that it is safe for your wet clutch. There are a hundred oils on the market that meet these specs. I personally recommend Maxima!

(A note to the wise! Find yourself an API SG rated oil to run in your car or truck, and get an extra level of protection! I run nothing but Redline!)