How To Save Money On Motorcycle Engine Oil

Choosing a Product That Works Without Breaking the Bank

John Lavina (July 2010)

When choosing an oil product for your motorcycle, it helps to actually know what the symbols and terms on the packaging mean.  And if budget is your main concern,  an understanding of the basic principles is essential.  Five minutes of review is all that stands between you and affordable protection for your motorcycle engine.

The Basics - Viscosity

Engine oil has a variety of properties. The flash point is a measure of when the oil will begin to burn, and the pour point is when the oil begins to stop flowing like a liquid.  Viscosity is a measure of the thickness of the oil.  As oil heats up it gets thinner and more fluid, so it's lubrication potential declines.  Use the viscosity index on the label to predict how well an oil product resists breakdown and thinning as the engine temperature rises.  The higher the viscosity index, the better. 

Refining Techniques - Group II or Group III

There are two common techniques by which crude oil is refined. The first technique is a clay-solvent process by which clay is added to crude oil to soak up the unwanted aromatics, sulfur and nitrogen compounds.  After the clay has soaked up these elements, the oil is diluted with a solvent such as methyl-ethyl-keytone or toluene and then frozen. The good parts of the oil will remain a liquid while the unnecessary parts will solidify and be thrown away.  This procedure often leaves behind a large amount of paraffin and wax, which can build up in your engine as sludge but the process has been around since 1930 and still accounts for half of all motor oil.  Oil refined this way is the cheap oil, not the high end stuff, and it is often only about 85% oil and up to 15% paraffin and wax.

Hydro-Isomerization process is an additional process that actually reshapes the wax and paraffin molecules into a useful substance that will not damage your engine.  Chevron licenses this patented process, called Iso-DeWaxing to allow others to manufacture Group II and Group III oils.  The end result is the higher quality, high performance oils, which are about 97% oil and only 3% wax.  This is what you want, so look for Group II or Group III on the packaging.   

Weight - What does (10w-40) mean anyway?

The '10' stands for 10 weight.  The 'w' does not actually stand for 'weight', but for “winter conditions below freezing.”  The '40' indicates the effective weight of the oil at the temperature of boiling water.  Since water boils at 212º F, oil marked as 10w-40 would indicate that the oil would be no thicker than 10 weight oil at 32º F, and no thinner than 40 weight oil at 212º F.  Prices are generally the same for the various weights, so just be sure to use the weight recommended by your manual.

What type of oil should I use?

As a casual trail rider, you would want to aim for the middle of the pack in terms of price and quality.  In most cases, you get what you pay for, so this should be easy to accomplish.  

It makes sense to choose an oil product that has the API seal or the JASO seal of approval on the bottle. API stands for the American Petroleum Institute, and it signifies that the company has paid a license fee to the API to have them independently test their product to ensure that it passes an applicable standard.  If the bottle does not have the circular symbol and just says API, this usually means that the company claims that the product meets API standards but has not submitted their product to the API for independent testing.  The testing process is expensive, so there can be sound motive for a small company not to do this, even if their product is worthy.

JASO stands for the Japanese Automotive Standards Organization. This is an organization that has developed their own tests that are designed for use by motorcycles.  

Do I Have To Use 'Motorcycle' Oil?

Obviously, if you have a two-stroke, none of this applies to you, but for some types of four-stroke trail bikes, you can get away with just using regular motor oil designed for passenger cars.  (If you're cringing right now watch out!  You may soon be hanging out at the track with your shirt off, polishing your rims with a lambskin cloth.)

For the most part, automotive and motorcycle oils are very similar.  Since most cars have a separate transmission fluid to lubricate the transmission but some dirt bikes rely on the engine oil to do both, you need to know something about which type of bike you have.  A motorcycle generally runs at higher rpm's than a car, so the oil will get hotter, and you'll want a highest viscosity rating you can afford.  But many of today's smaller passenger cars can rev to 6-8000 rpm, so you can find high quality everyday oils that will do the trick.  Street rockets may rev to the moon, but even a 4-stroke motocrosser of today will begin to dribble-off at 8-9,000 rpm.  If you ride a Honda XR or something similiar, you are dealing with even lower RPMs.  

Since we are mostly talking about trail riding here, it's safe to say that chosen carefully, most trail bikes will actually operate just fine for many years on regular motor oil for passenger cars.  Now that you know how to read the packaging, you should have no problem saving a few bucks without killing your motor.   And remember, it's a dirt bike, not an Italian sports car.  Make sure you spend less time pampering it than you do riding it.