Mike Guillory, June 2002
Along with keeping
things adjusted properly, using a good quality motor oil and
changing it regularly is the key ingredient to keeping your
motorcycle running happily for a long time. You cannot go wrong
using one of the various "motorcycle-specific" oils, now available
also from some of the major oil companies. However, many
motorcyclists object to the higher prices of those oils and for
convenience prefer to buy oil at their local automotive supply
store, which is a still a good option. This article will provide you
with information to make an informed choice.
So how do you make
an intelligent choice? Will $1.00 a quart automotive oil work okay
or do you need to pay $4 to $12 a quart for "motorcycle" oil? You
have to answer that question yourself, but here are a few facts to
help you make the best decision for your situation.
The owner's manual
of your motorcycle probably says something very similar to the
Use only high
detergent, premium quality motor oil certified to meet API Service
Classification SF or SG (shown on container). The use of additives
is unnecessary and will only increase operating expenses. Do
not use oils with graphite or molybdenum
additives as they may adversely affect clutch operation." That's
pretty clear. But what do you do since automotive oils now say on
the container "meets SL Service?" That's easy! By consensus of the
API and the manufacturers, the current SL classification meet all
requirements of SF, SG, SH, and SJ plus all earlier API gasoline
categories. The current SL actually offers some additional
benefits over the older classifications. So, if the motorcycle
requirement says "SG", be confident that "SL" indeed meets that
Vanishing Zinc and Phosphorous
It is a fact than
many SL oils now contain lower levels of ZDDP (the zinc/phosphorous
extreme pressure additive) and that is a big concern to a lot of
motorcyclists. ZDDP is a last resort protection against
metal-to-metal contact. Whereas a few years ago the zinc level was
typically 0.12% to 0.15% in SG automobile oils, some SL oils now
have as little as 0.05%. However, this in itself may not be a
problem since normal operation of a motorcycle on the street would
never result in metal-to-metal contact any more than it would in
your automobile. Remember these SL oils meet the most demanding
protection requirements of modern, high-reving, powerful 4-stroke
automobile engines (among others). And there is no reason to believe
the lubrication requirements of street motorcycles is measurably
However, if you
race you probably need higher levels of ZDDP and should use
appropriate oils or ZDDP additives.
opportunity to bridge this perceived gap between motorcycle oils and
automotive oils, many traditional oil marketers like Castrol, Mobil,
Pennzoil, Quaker State, and Valvoline now sell their own
"motorcycle" oils at very competitive prices, and alongside their
automotive oils. I have found them at several of my local autoparts
stores and even at one WalMart store. Call or visit the auto supply
stores in your area and ask. Even if they don't routinely stock
them, they probably can order a case for you at substantial savings
because their mark-up is generally quite a bit less than motorcycle
Although not a
motorcycle oil, oils with the designation "Racing Oil" are not
intended for street use, generally meets "SG" requirements and has
somewhat higher levels of additives, like ZDDP. An example is
Valvoline's VR1 Racing oil available in 20w50 weight. These should
work fine in our motorcycles.
Some are concerned
that the new "energy-conserving" motor oils may have "friction
modifiers" which will cause clutch slippage. Since that is a
legitimate concern it is best to use only oils which are
NOT "energy-conserving for motorcycles with wet
clutches." Read the back of the container. It clearly identifies
this. In general, only the very lighter oils, like 10w30, 10w20,
5w20, are energy-conserving. All 5w40, 5w50, 10w40, 15w40, 15w50,
and 20w50 oils which I have found are not
energy-conserving and can be recommended for general motorcycle use.
It is commonly mis-stated
that "SJ and SL oils have friction modifiers which will cause wet
clutch slippage." In reality, all oils have friction modifiers,
that's how they work. ZDDP itself is a friction modifier. The real
issue is to avoid getting the friction so low, with very thin oils
containing extra amounts of friction modifiers, that clutches will
slip under normal use. Stay away from energy conserving oils and you
should be fine, if your clutch is in good working order.
synthetic vs. semi-synthetic vs. "dino" oils? All motor oils have
several special additives formulated into the oil to protect from
corrosion and wear, plus detergents to keep combustion products in
the oil. For normal (non-extreme) use, "dino" oils protect as well
as the synthetic oils. However, if you plan to race, run at
extremely high temperatures, or plan to extend oil-change intervals,
or simply want the best, then a synthetic or semi-synthetic may be
your best choice.
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.
- What is a
reasonable oil-change interval?
Most manuals recommend not to exceed 8,000 miles after break-in.
But short-trip riding is considered severe service and the most
common oil change interval is 3,000 to 4,000 miles. However, a
long trip is the easiest service for the oil and going 6,000 to
8,000 miles between changes while on a cross-country ride is
routine. Also, the use of synthetic oils can easily double the
changing the oil even more frequently, like every 1,000 miles,
prolong the life of the engine?
Not very likely, because even at 3,000 to 4,000 miles, the oil and
additives are not degraded very much. Changing more often just
- What about
the claims that motorcycle-specific oils contain "special polymers
which are resistant to breakdown caused by motorcycle
Oils usually require the addition of polymers, called VI
improvers, to create a multi-viscosity oil, like 10W-40. Whether
it is a motorcycle oil or an automotive oil, all polymers are
subject to some degradation in the transmission. Full synthetic
oils tend to have less polymer than conventional oils and
therefore degrade less.
- Why are
motorcycle oils so much more expensive than automotive oils?
Cost of doing business is higher per quart of motorcycle oil.
Large oil companies make so much more product that their profit
margin per quart does not have to be so high. That's why the newer
motorcycle oils being marketed by some oil companies are only
marginally more expensive than their automotive counterparts.
- What about
the claims by specialty motorcycle oil manufacturers, that their
oil is better?
That's a good one. Next time you hear that line, simply ask, "What
evidence do you have?" I've never seen any. If you do get any,
please let me know! I don't believe that there is any.
Now, armed with all
this information, you are ready to make your choice between
automotive oil and motorcycle oil. Either will work fine. Your
motorcycle probably cannot tell any difference. There are many
riders, the author included, who use nothing but good quality
automotive motor oils. There also are many who use nothing but
motorcycle oils. All indications are that both choices work equally
well because motorcycle engines are designed so well that the oil
really doesn't make any measurable difference. As long as it meets
SG, SH, SJ, or SL service requirements.
In the past several
years, various reports went around regarding independent studies
that showed "automotive" oils that are not
energy-conserving (EC) work just as well as motorcycle-specific oil
and in many cases better. In former revisions to this article I
listed the oils I found locally (Houston, Tx) that were 10w40 and
heavier and not energy-conserving. I've discontinued that as it adds
little value. All one needs to do is look at the back of the oil
container where the lower half of the identification circle will
have the words "energy conserving" if it is. Don't use those in wet
clutch motorcycle applications, as they may cause clutch slippage.
If the lower half of that circle is blank, as all 10w40 and heavier
oils should, that means it is NOT energy conserving and should be
fine in wet clutch applications.
My favorite oils
and the ones I most mostly recommend for motorcycle use, are the
"heavy-duty" oils. They are commonly misunderstood, and often
referred to as "diesel oils." They are NOT energy conserving, have
higher zinc levels, as high as 0.16%, and by virtue of their
multi-duty have a better engine protection package than an oil that
is only rated "SL". These heavy-duty oils are rated SJ or SL, plus
CH-4. They are currently closer in formulation to the motorcycle
specific oils and to the "SG" oils that many motorcycle makers
recommend. Following are some examples of these oils, generally
15w40 oils by industry convention. There may be several other 15w40
oils that I am not familiar with.
- Castrol RX Super
- Chevron Delo 400
- Mobil Delvac
1300 Super 15w40
- Quaker State 4X4
Synthetic Blend 15w40
- Shell Rotella-T
15w40 (my personal favorite)
- SuperTech 2000 (WalMart)
- Valvoline All
- Castrol Syntec
Blend Truck and 4X4 15w40
Synthetics - for Maximum Protection
For years Mobil One
15w50 has been a favorite of motorcyclists. In recent years it has
gone from its original formulation to an improved SJ "TriSynthetic",
and more recently as SL "SuperSyn." In May and June of 2002 some
emails have gone around about Mobil One 15w50 no longer being
suitable for use in motorcycles. As far as I have been able to
investigate, that is a false concern. I was assured by Mobil
directly that Mobil One SuperSyn remains a suitable oil for
motorcycle use, although they naturally recommend their motorcycle
In contrast to
that, recently Castrol has been recommending that their 5w50 Syntec
is NOT appropriate for motorcycle use because of additional levels
of friction modifiers.
A fairly new player
in the synthetic market is Shell with Rotella-T Full Synthetic 5w40.
It is not energy-conserving and according to Shell performs
competitively with Mobil Delvac One full synthtetic, which means it
offers even more protection than does Mobil One 15w50. At least one
motorcyclist has reported to me good results so far with his use of
the new Synthetic Rotella-T. I haven't tried it yet.
Delvac One would be
one of my highest recommendations but I don't know where to buy it.
For those who may have connections with a long-haul trucking
operation, where Delvac One is known to be used in oil change
intervals up to 150,000 miles, I suggest trying to get some if you
want a superior oil.
There are a number
of other synthetic and semi-synthetic oils available and I have no
reason to believe they are in any way inferior. Just follow the
advice and use one which is not energy conserving.
Note: Be sure and use the recommended viscosity range,
e.g. 10w40, 20w50, etc. for the climate in your area. In general, to
protect your motor use the heaviest oil you can that still meets the
manufacturer's guidelines. For example, 20w50 is better in warm
weather than 10w40, because it gives you a thicker oil cushion
between bearing surfaces at operating temperature. For racing, a
thinner oil will offer less resistance and thus more power, but will
offer less protection.
believe in these oils and use nothing else in my motorcycles. As
always, you have to make your own, informed decisions.
A Note on
Since it is
generally accepted within the industry that current classifications
also meet all older ones, there can legally be no warranty issue. In
fact, some oils actually say on the package "SG" in addition to SH ,
SJ and SL. However, if any of the very newest motorcycles specify
oil meeting the new JASO, or other motorcycle-specific oil
specifications, and no reference to "SG" or similar automotive
specs, then you may have a potential warranty issue so behave
And finally, it is
gratifying to have received so many emails the past three (3) years
from motorcyclists finding this oil and oil filter information
useful to them. Keep them coming. I am happy to help, and I plan
further updates as things change significantly.
The author is a
Chemist, retired from a major Oil and Chemical Company, after a
career in the Quality Assurance of Fuels, Lubricants, and Chemical
products. He and his wife both ride.
questions may be sent to
Mike in Houston
'94 VFR750 "XENA"
'85 V65 Magna "YELLOW SONIA"