Mythbusting: Oil .. weights, synth-vs-dino, and promises.

Hey all. I'm no-one. Just yet another 50 year old dumass with a public school education (I just barely graduated from a rural High School with easy standards). So I'm actually about two ticks above average (which is friggin sad and scarey at the same time!). So in any case, I'm no authority on anything other than my own opinions. On those, I am the formeost authority on the planet! Haa! I'm also a gnoob at this forum, so I have even less cred. No sweat .. this thread ain't about my integrity or my social credit score. Just wanted you to know *who* I am. I'm just like most of you ... a person wanting some answers .. answers that do not involve "buying into" anything.

Over the last three weeks I've devoted more time than I am willing to admit in public to learning which oil to run in these XJs as well as my 1984 Honda Magna v45 (a 700cc water cooled bike). It's been a HAUL. Wading through the absolutely HUGE piles of nothing but *opinions* backed up with even more tons of conjecture and the dreaded "common sense" (I shudder every time I hear someone use that phrase .. that and "Everybody knows that" will get my radar on red alert). Shutting the hell up shortly here ... here's what I've learned ...paraphrased.


WEIGHTS.

20w50 (we'll use this as an example): This is a promise to you on the label. It is the oil telling you "I promise not to become any thicker than straight 20 wt does when straight 20 wt. is chilled to 30 degress" And it's also saying "I promise to not get any thinner than straight 50wt does when straight 50 wt is heated to 100+ degrees". (Btw .. the "w" stands for "winter" not "weight").

So said another way ... : "I promise to get no thicker in the Winter than straight 20 weight does in the winter. And I also promise to get no thinner in the summer than straight 50 weight does in the summer.".

Those weight numbers DO NOT mean:

*** "The oil gets thinner when it gets colder". Nope. In other words, it does not "turn into" 20 weight when it gets colder. ALL OILS get thicker when they get colder. So 20w50 is saying it will get no thicker than straight 20wt does when it gets that cold.

*** "The oil gets thicker when it gets hot". No again. It does not actually "get thicker" (as if it were to turn into 50wt when it is warmed). No. ALL OILS get thinner when they are heated. All 20w50 is saying is that it will get NO THINNER than straight 50 weight does when straight 50 weight is heated.

So then ... there's the WEIGHT NUMBER issue settled once and for all.

SYNTH vs PETROLEUM:

This is too easy. The phrase "Synthetic oils" USED to mean that oil was pumped from te dirt and literally broken down into molecules. Then those molecules are used to build something from them. Nowadays, "synthetic oil" means that the oil has basically one specific polymer chain length. How it is achieved is no longer an issue. Synthetics are now directly refined intead of being broken down dino and rebuilt into Super Oil. Ok .. there's that part. Now .. the myths.

Here's the one thing you need to know about synths. They stay "20w50" twice as long (or more) than dino 20w50. That's it. Period. Dino simply breaks down much faster than synth. After that, everything else is total BULLCORN.

*** "Synths are thinner than dino": Synth is NOT thinner than dino .. it can be made into a much better "thin oil" than dino can, so it is used more frequently for that purpose Why? Because synth makes for a more stable oil that remains as advertized and in today's zingin' hi-revvers oil gets the PISS kicked out of it. Dino has too many of the "wrong polymers" to stay alive as long as synth does. Consequently when you see the thinner oils the high-strung engines of today need, it is typically synth.

*** "Synth gets too thin when it gets hot and then leaks past the rings bla bla." BS. Utter crap. It's no thicker, or no thinner than the RATING ON THE BOTTLE. Now then .. THIN OIL (no difference whether it's synth or petro) will get too thin and cuase problems .. but again, since most thinner oils happen to be synthetics, many of the muppets out there firmly believe that "all" synths get thinner when heated. Nooo .. ANY 5W30 is going to perform differently than expected .. synth or petro.

*** "Synth is better at removing heat than dino:". Nope. FRESH OIL is better at removing heat .. and synth stays fresher longer .. sooo .. you get the rest, right?

So in summary, I've found that after you get the proper "weight" of oil for your bike, everything else after that is personal preference. Now then, keep in mind that this thread does NOT address the ratings issues. The JASO-MA and such. Those are pretty straightforward as well. As is the issue of using modern car oils in older motorcycles .. short verion .. DON'T DO IT. The EPA laws have mandated that the proper additives that old biks need are to be removed from car oils. So these days THERE IS A BIG DIFFERENCE IN CAR OILS vs OLD BIKE OILS. In the past the situation was not so. But today, you either go with a "safe bet" (as in an oil that is exempt from the EPA standards for cars .. like diesel oil, and motorcycle oil, etc ..). Or one of the JASO-MA (wet clutch spec'd) specific products. The JASO-MA standard was created at the insistance of the motorcycle industry to insure that a standard for wet clutched engines was in place to protect these designs. Otherwise oil for these bikes would be impossible to find, and bike factories would have to resort to using diesel-type oils. I'm glad the factories put their foot down, their efforts make certain we are not shoved under the mat.

All I am addressing here is the weight numbers and the synth vs dino thang. Now here's the deal ... every bike reacts differently to different oils. Shifting smoothness, etc.. So that is the "personal preference" part that YOU and ONLY YOU can work out. All I've done here is give you an understanding of what the basic numbers mean. It's up to you to decide if you want the promised idea of synth staying it's advertized weight longer than dino (and the associated costs that go with it) or not.

Get those addidtive and JASO/clutch numbers decided upon (if you're like me you'll chicken out and go with the safe bet of using diesel ... there is no guessing .. it has none of the wrong stuff/clutch killers, and all of the right stuff/additives. It's also a bit tougher and deals with the sheer loads and the way the tranny gears beat the hell out of the oil). Then find the proper weight .. make purchase, oil bike ... ride.

I hope the "viscosity numbers on the bottle" are easier to understand for you now. I know I "get it" better these days. And some of the myths around synth are just comical! I hope this was of some help.

Thanks ..

Holeshot.

 

After proofing this post, it kinda reminded me of the way some folks come off with stuff like this:

"The frame is made out of chrome moly. And cr/mo is lighter than steel, everybody knows that!"

Chrome moly is NOT lighter than steel (it weighs the same), it is STRONGER than steel which allows you to make parts such as frames out of thinner materials .. thereby making the frame lighter.

I love "common sense". The first question it brings forth is ... "Sense common to whom?".

 

Re: Mythbusting: Oil .. weights, synth-vs-dino, and promise

Well done.

I am starting to be concerned about the additive package (or lack thereof) in diesel oils. Some of them have begun carrying the SM service classification, which I believe is a catalytic converter friendly classification. To me that implies less of those catalytic converter destroying goodies we want in our oil.

**EDIT** I noticed at the store today that the Rotella T 15W40 carries the JASO-MA service classification. Should be ok for motorcycles. The Rotella T 5W40 synthetic on my shelf also carries the JASO-MA

 

". . .every bike reacts differently to different oils. . ."

Just wanted to add that my 900's starter clutch can't handle synthetics, but my 750 can. You have to be prepared to dump that expensive oil right out if you want to see if your particular XJ can handle it. And I LOVE synthetic !! Makes me feel all warm and fuzzy.