Picking the Right Engine Oil for Your Bike

Oil is essential to motorcycling. Your motorcycle uses several kinds of oil for various purposes, from engine oil to transmission fluid to fork oil to axle grease and more. You may be using petroleum-based oils, synthetic oils or even organic oils, all at the same time.

Petroleum oil has been around forever, but it really took off as an industrial product when the Pennsylvania Rock Oil Company of Connecticut drilled the first known successful oil well in 1859. From there, it was off to the races, as oil drilling led to oil refining. Harnessing the power of petroleum oil fed the Industrial Revolution.

If you’re riding a gasoline-powered motorcycle, your bike uses engine oil for lubrication and cooling. Even if your bike is liquid-cooled with a radiator and antifreeze, engine oil still moves heat away from critical interior components in your power plant.

The safest way to keep your motorcycle running well is to use the oil that your manufacturer recommends for your bike and riding conditions. Somewhere in your owner’s manual and shop manual, oil is specified. Most manufacturers sell their own branded oil blend, making the choice of oil even easier. Of course, bike-specific branded oils are often more expensive than general brands, and may not be available at retail outlets other than authorized dealerships. That doesn’t mean that you can’t use other oils and still get the same results.

There are three basic types of engine oil: petroleum, synthetic, and synthetic blends.

Petroleum oils consist of mostly refined petroleum, treated with chemical additives to enhance its performance, fix its viscosity and maintain its working life. Most classic bike mechanics recommend traditional petroleum oils.

Synthetic oils are man-made products. Scientists have formulated combinations of chemicals that create a liquid that performs the same functions as petroleum oil, but with even longer lifespans and efficiency. Many mechanics recommend synthetic oils for newer bikes beyond the break-in period and for bikes that are ridden for long distances.

Synthetic blends combine the best of petroleum and synthetic oils. They move heat better than pure synthetics, and retain the right levels of viscosity when they are cool, making cold starts safer. New synthetic blends emerge every year, as scientists continue to research and improve oil blends.

Once you’ve identified the right type of oil for your bike, you have to find the right weight. The Society of Automotive Engineers (SAE) rates oils for weight or viscosity. Oils may be single weight – for instance SAE 30 or 30 weight oil. Few modern bike manufacturers recommend single weight oils. Most recommend multi-weight oils that are formulated to get thicker (higher numbers represent thicker oils) when they warm up. That means that the oil is thinner for cold starting, and then gets thicker as the bike reaches operating temperature, providing better protection against wear. The range is represented by a series of numbers and letters. For instance, 10W-30 oil is formulated to perform like a 10-weight oil when cool; then it gets more viscous like a 30-weight oil at operating temperature. The “W” in the name refers to “Winter,” not “Weight.”

Okay, there’s a lot of information there, and I haven’t even taken a deep dive. What does all of this mean to you when you’re thinking about your bike?

Simply put: Follow the manufacturer’s recommendation for the proper type and weight of motor oil in your bike when you perform an oil change.

If you have to add oil between changes, add the same type and weight of oil to your engine. Don’t mix synthetics and conventional petroleum oils, and don’t mix weights.

There’s a difference between motorcycle oils and car oils. It’s all chemical, and it mostly affects bikes that have shared engine and transmission oil sumps. Car oils have additives that reduce friction for fuel economy. Turns out that motorcycle transmissions need more friction to operate properly, so be sure to use motorcycle oil whenever possible.

The nightmare scenario has probably occurred to you, especially if you’re a motorcycle traveler. You’re at a gas stop in the middle of nowhere, and you notice that your bike is low on oil. You’ve been diligent about using the right oil, but you don’t have any oil with you on your trip. The gas station only has automobile oil. Are you better off continuing your ride with low oil, or should you add mismatched oil to your tank?

The answer is easy: Add the oil that most closely matches your specs. Make sure to match oil type (conventional, synthetic or blend), and weight. If you can’t match the weight, make sure that the high number is not higher than your spec oil. Running with the right amount of oil is the most important thing – don’t overfill or under fill.

At the next opportunity, stop in at a shop or dealership and perform a full oil and filter change and get your bike back to normal.

There’s a lot more to know about oil, but knowing and following these essentials will keep your bike healthy and running right.