This article was written by Mike Guillory and he has
graciously allowed me to post it here. I think it is offers an excellent
perspective and discussion on oil! It certainly has helped to shape my opinion
on this complex subject. And to frequent visitors, this article was updated in
October 2000.
Brief Introduction
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 for a long time. At the bottom of this article
is an addendum which lists current non-energy conserving SJ oils which may be
suitable for our motorcycles.
Price of Motor Oil
So how do you make an intelligent choice? Will $1.00
a quart automotive oil work OK 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 modern motorcycle will say
something very similar to the following:
"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 all
automotive oils now say on the container "meets SJ Service?" That's
easy! By consensus of the API and the manufacturers, the current SJ
classification meet all requirements of SF, SG, and SH, plus all earlier API
gasoline categories. The current SJ actually offers some additional benefits
over the older classifications. So, if the motorcycle requirement says "SG",
be confident that "SJ" indeed meets that requirement.
Real World Test Results
Are there any "real world" examples of long
motorcycle engine life using automotive oils? There's 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!
A Little Technical Discussion
Some have incorrectly said the newest SJ oils (all
automotive oils are required to meet SJ Service classification) no longer
contain zinc and phosphorous additives which protect against wear. The truth
is, the levels of these additives have a limit, but the limit is high enough
to offer premium levels of protection in gasoline-powered motors, including
our motorcycle engines.
Some are concerned that the new "energy-conserving"
motor oils may have "friction modifiers" which will cause clutch
slippage. Many motorcyclists, this author included, have used these
energy-conserving oils with no clutch slippage. However, increasingly there
are reports that these oils are causing clutch slippage and starter engagement
problems in some motorcycles. Therefore, it is best to use only "SJ"
oils which are *not* "energy-conserving." Read the back of the
container. It clearly identifies this. All 5w50, 10w40, 15w40, 15w50, and
20w50 oils which I have found are *not* energy-conserving and can be strongly
recommended for general motorcycle use. Conversely, all 0w30, 5w30, and 10w30
oils I found *were* energy-conserving, as required by the USA government.
What about 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, or 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.
Frequency Asked Questions
- 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 oil-change interval.
- Will 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 wastes
money.
- What about the claims that
motorcycle-specific oils contain "special polymers which are
resistant to breakdown caused by motorcycle transmissions?"
There are no such polymers. Oils often require the addition of polymers 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. If this bothers you alot, use a synthetic oil. Synthetic
oils require little or no polymer, so viscosity change is very small.
- 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. Some motorcycle oils may actually offer less
protection than SJ automotive oils.
- 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?" Chances are, there is no evidence. If you do
get any, please let me know!
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, or SJ Service requirements.
Addendum
In the past year or so, some notes went around
regarding several independent studies that showed "automotive" SJ
oil that *is not* energy-conserving (EC) works just as well as
motorcycle-specific oil, and in many cases better. So, I decided to compile a
current list of oils that meet this requirement in my part of the country.
Hopefully it will help some of you find these oils, if you want to use them.
They are listed alphabetically. All should work well for motorcycles.
Conventional Oil ('dino') - 10w40 and 20w50
- Castrol GTX 10w40; 20w50
- Chevron Supreme 10w40; 20w50
- Exxon Superflo 10w40;20w50
- Mobil 10w40; 20w50
- Pennzoil 10w40; 20w50
- Quaker State 10w40; 20w50
- Texaco Havoline 10w40, 20w50
- Valvoline 10w40; 20w50
- Valvoline VR1 Racing 20w50
Heavy-Duty Oils
The following are all 15w40 oils which, by industry
convention, are formulated for both diesel and gasoline engines, designated as
API CH-4 and SJ. These offer the highest levels of protection and are among
the best general-purpose oils for motorcycles.
- Castrol RX Super 15w40
- Chevron Delo 400 15w40
- Mobil Delvac 1300 Super 15w40
- Pennzoil Long-Life 15w40
- Quaker State 4X4 Synthetic Blend 15w40
- Shell Rotella-T 15w40 (my personal favorite)
- Castrol Syntec Blend Truck and 4X4 15w40
Synthetic Blends (see notes below) - 10w40 and
20w50
- Castrol Syntec Blend 20w50
- Quaker State 4X4 Synthetic Blend 10w40
- Valvoline Durablend 10w40; 20w50
Full Synthetics - for Maximum Protection
- Castrol Syntec 5w50
- Mobil 1 15w50 (a popular choice)
- Pennzoil Performax 100 5w50
- Valvoline Synpower 20w50
Notes: These are all the major brand
non-EC oils I find at my Houston-area auto-supply stores. Different parts of
the country will have a different subset.
Regarding synthetic "blends". These blends
typically contain about 25% to 30% synthetic base. It is not clear that they
offer measurable benefit over a 100% 'dino' oil. But they also don't cost much
more.
Important 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.
I personally believe in these oils and use nothing
else in my motorcycles. As always, you have to make your own, informed
decisions.
A Note on Warranties
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 of the oils above, like Pennzoil and Havoline,
actually say on the package "SG" in addition to SH and SJ.
And, finally, it is gratifying to have received so
many emails the past 15 months from motorcyclists finding this oil and oil
filter information useful to them. I am just happy to help, and I plan further
updates, but only when things change significantly. Please refer to Oil
Filter Alternatives - Honda Motorcycles also by Mike Guillory for a
comprehensive review of various oil filters.
Web Master's Note
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.
Mike in Houston
'94 VFR750 "XENA"
'85 V65 Magna "YELLOW SONIA"
