A motorcycle tech explained it to me that the shearing effect of a transmission, and the spinning gears, break down car oils too fast. Car oils are designed with a certain viscosity limit, while wet-clutch oils are designed with another.

Apparently the clutch tears up the oil, breaks down the friction modifiers, and causes them to turn into a film. In a car engines, and lower compression cycle engines this "film" is simply burned up because the tolerances allow passage. In a higher compression engine with finer tolerances, the film turns to gum and sludge, and eventually compromises performance by causing a buildup. The film can also coat the clutch plates and cause slippage, and fraying of the fiber plates that leads to dangerous conditions in the trans.

The one thing that seems to make the most sense to me, is that ATV engines are generally under a lot more stress than a car engine. They are not only revving quicker and decelerating quicker, but they are bouncing around the trails, splashing through water, they heat up fast, they cool down fast etc..etc... all of this means more stress to the oil....

I pay between $6-$8 per quart for Amsoil, and I change it twice a year. I don't find the investment all that great for the protection it provides. I don't feel like I'm going out of my way to put it in. It's full synthetic (like Mobile 1) but it gives the trans protection of an motorcycle oil.

 

In some parts of the world, I am sure it is absolutely impossible to find motorcycle specific oils. Honda caters to an international market, and in a sense the owner's manual gives you an "out" if you have to run a car oil, by only forbiding the "energy conserving" oils. But, I don't think you will find any car oil that doesn't contain moly (the enemy to your wet clutch), and even if a car oil isn't energy conserving it simply is not the BEST choice that one can make either in terms of the clutch or protection for transmission gears.

When you combine that with the fact that car oils (and now diesel oils too!) have gotten downgraded in terms of engine protection at every new classification since SG, it is clearly not the best choice to run a car oil, particularly here in North America where we have so many different motorcycle oil choices.

In a way, I think that the large number of choice in oils that folks have here confuses them, so they just grab whatever cheapie oil they find on the shelf and run out the automotive store door......proving that ignorance IS bliss!

 

Hard to find an energy conserving oil in a third world country,usually just basically dino oil ,

Say vinson A Z400 has adry sump system not a wet clutch ,so no conflict with oils in the motor .

 

deanz 400-YOU ARE OBVIOUSLY CONFUSED!!!

The Z400 and its clones absolutely have an integrated engine/transmission that share the same oil, and a WET CLUTCH!

The Z400 is a DRY SUMP engine (or at least a semi-dry sump), but THAT HAS NOTHING TO DO WITH ITS WET CLUTCH! All a "dry sump" means is that the majority of oil is contained in a tank, outside the crankcase. The advantage of this is that the engine does not need to be so tall, and the crank doesn't have to thrash through so much oil (which would rob power), plus putting the oil outside the engine adds cooling capacity. You can read more about this here: http://www.thumperfaq.com/oil.htm

 

Does anyone who has posted in this thread know of anyone who has lost a clutch because of using car oil?

 

I ran Honda HP4M (with moly), a JASO MB oil once by mistake in my 400EX and Z400. This was back in the day when the HP4 and HP4M bottles were the same color and you had to read the fine print to know whether it contained moly or not. I have to say that I never noticed any clutch slippage, but I didn't keep it in for long either once I learned my mistake.

But why obsess about just the clutch??? The worst thing is that car oils don't contain the levels of ZDDP that will help protect your transmission gears. To me, that's the way bigger issue, more than the clutch. I would for sure rather replace a clutch than a set of gears, I know that much!

***Personally, I want to play it safe with my expensive toys........and not spend my life trying to see what I can get away with!***

 

Reconranger, you never did answer my question.

 

I guess you will be crushed to know that I don't exactly read your stuff that carefully (heard it all before anyway!), so I don't exactly remember any question!

 

I see feathers and a beak!!!

For others that want to learn; here is what CRANE CAMS has to say about Rotella and Delo and synthetic oils. Wow, imagine that; one of the biggest cam makers in the world recomending a cheap oil that I have been talking about for years.
Crane cam Break-in sheet.
Due to the EPA?s mandate for zinc removal from most motor oils, proper flat tappet camshaft break-in procedureis more critical than ever before. This is true for both hy-draulic and mechanical flat tappet camshafts. As a point of interest, the most critical time in the life of a flat tappet camshaft is the first 20 minutes of ?break-in? during which the bottoms of the tappets ?mate-in? with the cam lobes.There are some oils with additive packages that are bet-ter for camshaft ?break-in?. These include: Shell Rotella T oil; Chevron Delo 400; and Mobil DELVAC oil. These oils are listed as diesel oils, but work great for flat cam-shaft ?break-in?. We also recommend the use of Crane Cams # 99003-1 Break-in lube or GM ?E.O.S.? (Engine Oil Supplement) Assembly Lubricant # 1052367. These should be poured over the lifters and camshaft prior to start up.CAUTION: We do not recommend the use of synthetic oils for ?break-in? because they are too slippery. This characteristic reduces the tendency of the lifter to rotate on the camshaft lobe and mate properly. Prior to install-ing the camshaft and lifters, it is recommended that the crankcase be drained and filled with new, clean oil. The oil filter should also be changed at this time.

 

Well it is not just a matter of burning the clutch up, it's a matter of slippage......

If the car oil is making the clutch slip a little bit all the time, you might not even know it. You might be losing power through the clutch, through a slight and constant slippage and there is a good chance you would never know it...