The Great Oil Debate: Some New Data?

fintip · Oct 13, 2012

Real World Test Results

Are there any "real world" examples of long motorcycle engine life using automotive oils? There is a good one in the June 1996 issue of Sport Rider magazine in a report called the "100,000 mile Honda CBR900RR." The owner used conventional Castrol GTX oil, 10W40 in the winter, 20W50 in the summer. He changed it every 4,000 miles, changing the filter every OTHER oil change. No valve clearance adjustments were required after the initial one at 16,000 miles. And a dyno test against the same model with only 6,722 miles showed torque and horsepower virtually identical. The 100,000 mile bike was even used for some racing. In a subsequent follow-up, the same CBR had passed 200,000 miles and was still going strong! Plus, many motorcyclists have emailed me with their very positive results using nothing but automotive oils for years in a variety of rides. Oils have changed over the past 10 years, but that just means we need to be more careful in our choices.
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--http://vfrworld.com/tex_vfr/tech/oil.htm

Preliminary Conclusions

The results of these tests seem to support some of the long-standing theories about oils while casting serious doubt on others. Going by these tests it would seem logical to assume that:

1.The viscosity of synthetic-based oils generally drops more slowly than that of petroleum-based oils in the same application.

2.Comparing these figures to viscosity retention for the same oils when used in an automobile (see later text by Prof. Woolum) would indicate that motorcycles are indeed harder on oils than cars.

3.The fastest and most significant drop in the viscosity of petroleum-based oils used in motorcycles occurs during the first 800 miles (or less) of use.
All of these results (1-3) agree with everything the oil companies have been telling us all along. However, the same test data also indicates that:

4.The viscosity of petroleum-based oils, whether designed for auto or motorcycle application, drop at approximately the same rate when used in a motorcycle.

5.There is no evidence that motorcycle-specific oils out-perform their automotive counterparts in viscosity retention when used in a motorcycle.

These last two results (4-5) definitely do not agree with what the motorcycle oil producers have been telling us. In fact the test results not only indicate the two motorcycle oils being outperformed in viscosity retention by the two automotive synthetic products. but even by the relatively inexpensive Castrol GTX, which is a petroleum product. This directly contradicts the advertising claims made by the motorcycle oil producers.
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Bottom Line

It could appear from this data, then, that there is no validity to the constantly-used argument that motorcycle-specific oils provide superior lubrication to automotive oils when used in a motorcycle. If the viscosity drop is the only criterion, then there is certainly no reason to spend the extra money on oil specifically designed for motorcycles. There does, however, appear to be a legitimate argument for using synthetic and synthetic-blend oils over the petroleum based products.

MCN's Conclusions

In speaking to a number of people involved in the production, marketing and distribution of motorcycle-specific oils, we could not find anyone who could present a valid argument for discrediting the testing done by Dr. Woolum. In general, they all tried to turn the conversation another direction by bringing up other possible advantages to using their products, while ignoring the viscosity-retention question. Yet without exception it is their own advertising that consistently brings the subject up, touting the special shear-stable polymers as the primary reason motorcyclists should purchase their products.

It is this practice to which we take exception, as we have been unable to find evidence to support these claims. In short, it seems to be nothing more than a clever marketing ploy designed to enhance their products' image and separate motorcyclists from their money.

MCN is ready to print any research or test results provided by the oil companies to support their claims of superior viscosity retention, with this one proviso: The comparisons must be against actual, SG-rated oil products that can be purchased off the shelf at the average auto parts store. Tests against generic, basic-stock mineral oil or against the lower-rated SE and SF oils would lack any credibility in a real-world context.

Despite more than six months of research, reading all the claims and counter-claims printed by dozens of industry experts and lubrication experts, MCN cannot and does not purport to know all there is to know about the differences between automotive and motorcycle oils. However, what we do know is that we can find no substantive evidence that using a high-quality, name-brand automotive oil in an average street motorcycle is in any way harmful or less effective in providing proper lubrication and protection than using the more expensive, motorcycle-specific oils.
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--http://www.nightrider.com/biketech/oiltest1.htm

bigfitz52 · Oct 13, 2012

There is no "debate." The question is NOT whether or not motorcycle-specific oils "offer superior lubrication compared to automotive oils, etc., etc."

What we KNOW, through real-world experience, is that in our particular flavor of 30-year old bikes there are components that don't perform well when using modern automotive oils. Those items being the starter sprag clutch and the multiplate wet clutch.

It has nothing to do with viscosity breakdown, etc. It has to do with whether or not you want your starter clutch to engage reliably.

hbwb · Oct 13, 2012

I use diesel specific oil like rotella.

bigfitz52 · Oct 13, 2012

What's the API grade on Rotella, out of curiousity?

I just noticed something else about the article.

It's dated. It's speaking in terms of API Service SG automotive oils; most JASO-spec motorcycle oil IS SG. Automotive oil these days is up to API spec SM or beyond; (the problem stuff.) I used Castrol GTX "just OIL" myself for somewhere around 30 years in my Norton, and it didn't need to be motorcycle oil. Then things changed (after the article was written, apparently.)

Sorry, fintip, it doesn't even apply to our present-day situation.

hbwb · Oct 13, 2012

Not sure but it is recommended by many for these older bikes because of its zinc content. They say these tappet camshafts need the extra lubricating properties of zinc which has been phased out of a lot of automotive oils.

Polock · Oct 13, 2012

mobil delvac 1300, API CJ-4, CI-4 PLUS, CI-4, CH-4, SM, SL.
Caterpillar ECF-3
Cummins CES 20081
works good in my lawn mower too

ski84 · Oct 13, 2012

Rotella T 15W40 has an API rating of SM but more importantly it meets the Japanese spec for wet clutches JASO MA. I have been using it in my FZ and it is excellent oil. I recently had my Rotella oil analyzed by Blackstone labs for my FZ and at 4000 miles it still had less wear than a typical oil at 2600 miles. They even said that I could up my service interval to 5000 miles should I choose to. When I use up my Castrol 4T stash I am going to switch over to it in my XJ...

fintip · Oct 15, 2012

You're right, fitz. I didn't realize oil grades changed so often, but I did know the article was dated. I just figured it didn't matter.

Turns out all three modern automotive grade oils are classed as "Energy Conserving", which are exactly what one of the articles above says to avoid in motorcycles, actually.

(I tried Rotella, by the way, and felt a performance loss and some strange iffyness in my last FJ compared to valvoline 20-50 motorcycle oil, so next time I used a mix. Didn't have the bike long enough after that to verify it was the oil, unfortunately.)

Super · Oct 15, 2012

I've been using Rotella 15w-40 (during the summer) in everything for years, with no issues. 83 900, 77 GL1000, a Subaru, several Jags; my Elantra has over 200k, I buy it by the bucket when it goes on sale at Walmart or CTC and have had zero issues. I use whatever is on sale in a 5w30 grade during the winter in the winter driven vehicles.

Almost 40 years of driving countless types of vehicles, I've never experienced any type of engine failure using regular oil changed on a regular basis.

Dave

happydog500 · Oct 16, 2012

One thing you have to take into account is that oil changed in about 2000-2002.
It's not the same anymore. It may of been OK to use certain type back when this artical was written, but the oil changed since then.

Chris.

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The Great Oil Debate: Some New Data?

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