Bike Oil vs Car Oil...

Motorcycle oil is what you should use. You can probably pick up a case & defray some of the cost.
Phosphorous and zinc are the primary lubricants in motorcycle oil. Calcium and magnesium are the acid neutralizers that are added. Each "upgrade" of the API level (SF, SG, SH) means less phosphorous levels. What that means in the long run, I don't know. They feel that the phosphorous content may contribute to shortened catalytic converter life. It would be wise to change out the "dino" oil each 1000 miles & a synthetic at no more than 2,000 miles, under normal riding conditions. By normal, I mean no overheating or riding in very dusty conditions. In fact, I change the dirt bike's oil once a month (1 quart!) as a matter of course. As soon as the break-in is over on my Meanie, it will be fed a diet of Golden Spectro. It is a synthetic blend. I use the regular Spectro in the dirt bike. It shifts butter-smooth since day one of using it. Spectro has always made a great bike-focused oil & is very well respected and used by many BMW riders. I believe they even make the oil for BMW, according to BMW's specs. And no, I am not a sales rep for Spectro. It sure sounds like it! But it seems that all the research I did on oils keeps coming back to Spectro. But whatever oil you use, buy quality motorcycle-focused oil in the correct viscosity and change it often.
I hope this helps your dilemma.
Regards.

The article is on several websites since it was printed in 1994 by Motorcycle Consumer News. I have the 15 page printout & it is good. This deals with the viscosity retention issue that was a concern back then. Since then, the issue has arisen of the newer "energy conserving" oils containing certain friction modifiers that do not agree with some clutches & apparently causes them to slip. I have only heard of scattered anecdotal evidence of this, however, mostly online. Regrettably, no official tests, that I know of, have been run to dispel this. The only reference to this was a tech article in Motorcyclist magazine (9/04 issue, page 87), that addressed this matter briefly, in one sentence. I quote, "Much has been written about "improper" oil harming wet clutches-making them slip, for example-but the evidence behind these claims is often hard to find." No further elaboration, since the article was about clutch tech.
Many riders use Amsoil & swear by it. Many riders used the earlier Mobil 1 synthetic but indicated that if Mobil added the friction modifiers to it, that they would stop using it. One may want to check out the Internet BMW Riders website & see what they say about oils in general. That article was an eye-opener. Again, my feeling is that the conservative approach to oils should be used until unimpeachable tests prove that it is OK to use automotive oils in the bikes. I will be the 1st to switch if this comes about. Maybe some riders on this forum can provide their experience using automotive oil in their bikes. It would prove interesting.
Regards

Brett, you have to buy distilled water at a pharmacy??! Your location shows South Africa. Please don't tell me they have proclaimed it a controlled substance and you need a prescription! I am not being wise, just shocked! One can buy it anywhere here.
Anyway, the bikes' manuals call for distilled water to eliminate mineral scaling buildup iin the cooling system. Heck, I wash the bikes with distilled water-it leaves no spotting from any minerals. You also need it for the battery, if you have the removeable caps. I also use it in the cars when I change out the coolant.
When you said you use Mobil S, I have never heard of that oil. It might even be that the container is not marked, "energy conserving" on the API label (if it even has an API label). If the grade is SE or SF, then it has a good amount of phosphorous in it. Across the pond here, the oil companies have to focus on light vehicles in order to help the car producers meet gas mileage standards. In fact, Ford has all but mandated that we are to use a 5W-20 oil in the newer cars because that helps Ford meet the minimum CAFE (corporate average fuel economy) standards for their vehicles, thus avoiding heavy government fines. With hundreds of millions of cars & trucks here, I think you can see what I am talking about. They've got to be putting cutting edge additives in our stuff, and that is what would concern me about using it in the bike. Even Kawasaki in their GTPP extended warranty will not cover parts damaged by using "improper" oils. Where you are, the regular oils may even be suited for a bike, unless they are marked, "energy conserving". I hope you can use the stuff to save some bucks.
Regards

Distilled water is cheap here. 52 cents a gallon. Spring water is more! My wife's expensive professional iron requires it. I wash the bikes with it because my own tap water is very hard. I use it for the trucks' cooling systems and for my cigar humidor. Lots of uses. Don't feel out of place for using it. It is the wise way to use the correct stuff.
I see you oil is API SL. I would not use it myself because of the lowered phosphorous/zinc content of the SL rating requirement. There are those out there that would say that there should never be metal-to-metal contact within a bike's internals. Most of the time, that is true. But it is not 100% reality. The one time you overheat can be the one that costs you an engine. The guys on the Yamaha Warrior website change their oil out immediately when they overheat after riding in traffic, etc. That is the cautious way. There is too much to lose otherwise. Liquid cooled bikes can also overheat. The oil has to be assumed to be toast after (or during) such an episode. The phosphorous/zinc additives give you that buffer zone of protection that you hopefuly will not need. If you need it, the oil has broken down enough to create metal-to-metal parts contact within the engine/transmission. Yes, there are the 10w-40, 20w-50, 15w-50 oils that do NOT have the energy conserving certification. My estimation of this is that they are probably OK to use, but only if I was pressed to lay Vegas odds on it. But would I use it myself? No. Not until there are credible studies to indicate otherwise. Perhaps if I were stranded somewhere & had no other choice...
I know that my attitude reflects extreme conservatism on this subject. This kind of debate has been going on for decades & may never be resolved without irrefutable scientific evidence. That probably won't come about in the forseeable future. Too bad. There a a lot of superb quality light vehicle oils out there.
Regards

You should not use an automotive oil that is marked as "energy conserving" in your bike. Such oils contain friction additives, such as molybdenum, which would likely cause clutch slippage/damage. Now the "gray" area. There are automotive oils that are not marked as energy conserving that bikers have been using for years. All the companies make such oils, and they come in weights like 20W50, 15W50, etc. The viscosity spread is larger than those of the energy conserving oils, which require less of the viscosity index improvers (which is one reason these oils are energy conserving) than the oils with a wider viscosity spread. To confuse matters further, the different API grades, SH SJ SL, etc. all represent an ongoing decrease (even in the motorcycle-specific oils) in phosphorous/zinc, which is the ultimate protector of metal-to-metal contact, should that occur. We are told that the stuff might be ultimately bad for our catalytic convertors. But even momentary metal-to-metal contact can occur in car or bike, i.e. overheating or a microsecond of starvation in a small, critical area for example. I take the path that the more phosphorous/zinc additives, the potentially better it is for our bikes. Yes, bikers have been using auto oil for years, but with this recent ongoing reduction in the protective additives, what does the future hold for engine wear for people who use auto oil in their bikes? I really don't know. At least during warranty, use a bike-specific oil. Otherwise, any repairs that are deemed to be oil-faiilure related will not be covered. I use only bike oil and change it out at 1000 miles. Some use Mobil 1 15W-50, and state that they have had good luck with it.