|This is one that can really get me in trouble if I’m not careful. An Oil Explanation. It is one of the most controversial and beat up topics in motorcycle discussion I know. I’m going to lay out a few facts and leave an opening to bow out gracefully.As pollution and gas mileage demands became more stringent, auto manufacturers had to come up with as many tricks as they could to stay within the limits set forth. One thing they found was if they could design engines that would operate with lower viscosity oil (thinner) overall gas mileage would increase because there was less internal fluid drag from the parts in the engine that pushed through the oil. Simply stated, it’s easier to run your hand through water than through molasses. Same effect in the engine. The trade off is that the thinner oil gives up some of its ability to stand up under severe conditions. As heat increases oil in general looses some of it’s viscosity and thins out even more. By-by to lubrication when this happens.New oil technology has helped the slimy stuff rise to the occasion and face the music that an engine throws its way but severe demands still override the tehno and here lies the rub. Some of the goodies had to be reduced in the new SJ rated oil to meet pollution requirements. Zinc dithiophosphate is of which I speak. This is the stuff that kicks into gear when the going gets rough. Zinc is the last resort when metal to metal contact is about to, or has been made. It is a “healing” metal that actually deposits itself in microscopic scratches and fills them in. Zinc is on the E.P.A. hit list of polluters and the quantity of this fine additive has been drastically reduced in oils manufactured in the last year or so that meet the SJ rating.
So does this add fuel to the fire of motorcycle oil vs. automotive oil? Yup, but I ain’t got the answer. The M.C. oil makers do not fall into the government guidelines because they are a “speciality” item. The cycle oil boys can keep the zinc at the levels it was previous to the SJ change. Do they? They say they do and for that privilege you get to pay 8-12 bucks a quart for some of that stuff. They also claim to use better base oils in their magic mix.
I myself am in a quandary about all this. Even the oil I use, synthetic Mobil 1, has gone SJ and I really don’t know if it is the same quality that it used to be. Does the zinc reduction demand the switch to M.C. specific? When my large purchase of the older Mobil 1 advanced formula runs out, I have a decision to make too. I hope by then more information has been made public so it will be a sensible decision.
No matter what, frequent changes are and will always be important. 2-3000 miles max. Remember as miles pile up, oil’s additives and viscosity break down and the only way to replace them is with an oil change.
Some more good information about SJ vs. SG oils can be found at:
I suggest you go to your favourite search engine (Infoseek) and type in: +oil (space) +motorcycle and have fun!!!
Oil Explanation Submitted by Bob Ratcliffe