Motorcycle Engine Oil

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Motorcycle Engine Oil

When Choosing a Product, It Helps To Know What the Symbols And Terms Really Mean

Most people know that engine oil not only helps cool certain parts of your engine but also helps prevent tiny pieces of debris such as carbon and dirt from getting where they shouldn't. Changing your oil regularly is one of the simplest things that you can do to prolong the life of your engine, but it's also important to be realistic. If you are not James Bubba Stewart, you don't need to maintain your bike like a factory team would do. You don't put on new tires on for every ride just because the pros do, so you don't necessarily need to buy high priced, strongly hyped motorcycle oil either.

When choosing a product, it helps to know what the symbols and terms on the packaging really mean, and for many types of bikes you may be able to skip the high dollar, high markup motorcycle-specific products and find a middle of the road product that meets the specifications in the manual and will keep your bike running great for years, at a reasonable cost.

The Basics

Engine oil contains many different chemicals that give it 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 begins to thin out, and become more fluid, so it's lubrication potential declines. This is measured by the viscosity index, and the more the oil resists thinning out as the temperature rises, the better the viscosity.

Refining Techniques

There are a couple of common techniques by which crude oil is refined. The first technique is a clay-solvent process in which clay is added to crude oil to soak up the aromatics, sulfur and nitrogen compounds. After the clay has soaked up theses 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, the process has been around since 1930 and still accounts for half of all motor oil. This is the cheap oil, not the high end stuff, and it is often about 85% oil and up to 15% paraffin and wax.

The Hydro-Isomerization process is what 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.

What does the (w) mean?

So what is that number followed by a lowercase 'w', a dash and a number? It actually does not stand for weight as you might expect. The 'w' stands for “winter conditions below freezing”, and the 40 means the performance of the oil at the temperature of boiling water, so 10w-40 would mean that the oil would be no thicker than 10 weight oil at 32° F and no thinner than 40 weight oil at 212° F.

What type of oil should you use?

As a casual trail rider, you may 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, and certainly... buying everything the magazines tell you to buy.)

For the most part, automotive and motorcycle oils are very similar.  A car does have a separate fluid to lubricate the transmission while some dirt bikes rely on the engine oil to do both, so you need to know which type you have.  People will say a motorcycle normally runs at much higher rpm's than a car, so the oil will get hotter, and you'll want a higher viscosity rating.  But then again, many of today's smaller passenger cars can redline as high as 6-8000 rpm, so this argument is becoming less pertinent.  Street rockets may rev to the moon, but even a racing 4-stroke dirt bike of today will begin to dribble-off at 8-9,000 rpm and throw parts at 11,000.  And if you ride a Honda XR or something like that, old or new, you are probably dealing with even lower RPMs.  We are talking about trail riding here anyway, and if you are over-reving too much, it doesn't matter much what kind of oil you use, you'll be rebuilding frequently.

So chosen carefully, some bikes will actually operate just fine for many years on regular motor oil, and it's safe to assume any bike that is being casually trail ridden does not really require the very highest priced motocycle oil products.  It is, after all, a dirt bike, not an Italian sports car.  Make sure you spend less time pampering it than you do riding it.