My brother has ran car oil in his quad since he got it in 93(93 warrior).Changed oil for the first time last year no problems.No joke either but he only rides ~10 times per year.

 

I think hondabuster has it right. Motorcycle and ATV engines (for the most part) share their oil with a transmission. The extreme pressure created by the sliding action of transmission gearing requires special additives designed to withstand that pressure. The trouble is, they also usually incorporate a wet clutch that does not like "friction modifiers" such as molybdenum or graphite. Honda manuals warn against the use of oils containing these additives.
I'm not saying you'll see dramatic wear and failures if you use the wrong automotive type oil, most of us never put enough miles on a motorcycle or a quad to readily see the results. What I AM saying is, why not use what the manufacturer recommends for the sake of saving a few bucks? I checked the price recently, and locally Castrol GTX cost $2.65 Cdn/litre, Castrol Grand Prix (motorcycle oil) cost $3.99 Cdn/litre, and Honda GN4 costs $5.35 Cdn/litre. So, if my oil change takes 2 litres, I'm saving about 5 bucks by using the automotive oil over what Honda recommends, and the Castrol Grand Prix would probably be just fine as well, I've used it in quite a few motorcycle engines over the years with zero problems.
If it were me, and I've done the same thing... I'd warm up the engine, change the oil and filter to the right stuff, and go about my business.

Chilly

 

Thats what I was thinking, glad I dont have to type it all out now, thanks!!

 

Motorcyle oil is not different than car oil, it's just a marketing ploy. Do a search on motorcyle oil, a guy posted some very informative links that showed lab testing of the various brands of oil. If you buy motorcyle oil, you are wasting money.

 

There is a difference in SG to SL( the current modern oil). It isnt marketing hype. Look in your owners manual, if they say to use SG on a 2004 wheeler, theres a reason. SG hasnt been the highest standard in 8 years, in fact ,try to find abottle of SG oil for a car, every thing youll find is SH or higher.
Honda doesnt care if you use hondaline oil or shell, just that you use nothing rated higher than SG.
Chances are, if you use SL oil in the atv, and even if you ride a whole year on it, no damage will happen. But if you ride hard, or let it get hot in a mud pit, or abuse the clutch, then you should have the recommended oil in the crank case.
There was a very informative article, in Motorcycle Consumer News, about a year ago which went into oils, in an unbiased way. They did chemical studies, and went into what the additives were, and how much was in each brand.
Its not just marketing hype.

 

I checked out some of the links on motorcycle vs. auto oil, and the issue is more clouded than I thought. I do think I'm beginning to understand the problem a bit better though. Most of the research has been on a private basis from what I've read below

http://homepages.paradise.net.nz/~hasl/oillinks.htm

http://www.xs11.com/stories/mcnoil94.htm

After reading both pages (the first one is more current, the second was posted in 1994) it seems that the issue we're faced with is just which additives are in which oil. Both websites agree that synthetic is better than petroleum based oil, but the more recent one ackowledges the problems that come from using oil that has friction reducing compounds such as graphite and molybdenum added. I checked some automotive oil I had kicking around, and both Castrol GTX 5w30 and Mobil 1 5w30 had labeling indicating they were "energy conserving".
The issue that Motorcycle Consumer News was most interested in was viscosity breakdown, how well the oil stood up to the abuse the bike was dishing out. There was little doubt that the bike was tougher on oil than the car was, no surprises there. What I'd like to see was a comparison of how well the transmission held up with different oils.
Neither the Honda 10w40 GN4 I use or the Castrol Grand Prix 10w40 I looked at even had the API circle. From experience with motorcycles I can say I've had no problems with the Castrol GP, and Honda recommends their own oil, naturally. I suspect their interest in doing so is twofold. Firstly, they make money on every oil change the ATV gets, and secondly, they know exactly what is in their own brand of oil, therefore they can recommend it without reservations.
I think that I'll keep paying through the nose for the GN4, at least for now, but I wouldn't lose sleep over having to top up with another brand of oil, as long as it wasn't "energy conserving" with additives that might cause clutch problems.

Chilly

 

Only thing I can add is that I have ran Castrol GTX in my streetbike for a few years and no problems with the wet clutch. It works just as good as Honda Oil.. I run the same oil in the YZF and it runs fine. I may step up to the Synthetic for the YZF though just because of the performace. The Castrol GTX works great for MOST wet clutch applications

 

Please!!! just change the oil!! Let these other experts continue generating worthless paper!!! LoneWolf[img]i/expressions/face-icon-small-cool.gif[/img]

 

i'd go to the owners manual first. BUT you can buy ATV oil at like CSK and Autozone for a reasonable price. you dont have to pay $5/qt, Valvoline and someone else makes it now too. Since I'm not a petroleum expert, I'd rather not take a chance. [img]i/expressions/face-icon-small-smile.gif[/img]