There’s something special about the freedom that comes with owning your own Harley—but with that freedom comes the responsibility of regular maintenance. If you’re an informed Harley Davidson owner, then you know that there’s more to choosing the right engine oil than just picking up a jug of motor oil from your local auto parts store. In this article, we’ll discuss everything you need to know about Harley Davidson engine oil, including the differences between motorcycle engine oil and car motor oil, what to look for in a good motorcycle engine oil, and the differences between using wet sump or dry sump lubrication systems on your bike.
Harley Davidson Engine Oil 101
How Is Motorcycle Engine Oil Different From Regular Motor Oil?
It can be tempting to think that all engine lubricants should be interchangeable—especially if they have roughly similar moving parts, right? Wrong. While both automobiles and motorcycles rely on rapidly moving metal components during combustion to get their forward momentum, the design of these engines is different and therefore the lubrication requires different properties. Here are some of the key differences between car motors and motorcycle motors:
1. Motorcycles have only one sump (or liquid collection area) whereas automobiles have multiple. Likely part of what drew you to your motorcycle was the beautiful simplicity of its design. Unlike a car, which has sumps for various fluids other than motor oil (like transmission fluid, for example), motorcycles rely on one sump to contain a fluid that acts as an engine lubricant, primary fluid, and transmission fluid. This means that motorcycle oil must not only lubricate the engine but cool and lubricate the gearbox and clutch as well.
2. Motorcycles not only have just one sump, but it is much smaller than an automobile sump. This means that there is less oil to do the same amount of work—which is why so many Harley riders recommend a full synthetic motorcycle oil, or at least a synthetic blend. Likewise, the pathways the oil must flow through are significantly smaller on a motorcycle than on a car, so the oil must be able to flow through small spaces quickly.
3. Motorcycle engines typically operate at higher speeds and temperatures than automobile motors. What this means is that your motorcycle lubricant must do everything a car engine lubricant can do, only in more extreme conditions. This, coupled with the fact that there’s less of it to go around due to the small size of the sump, means that you must be extra careful in selecting a motorcycle engine oil, as it must be capable of keeping things running smoothly even in high-heat or high-friction conditions.
4. Most motorcycles (except newer models) are air-cooled, whereas cars rely on radiators and coolant to keep the engine cool. Because the engine is so exposed to fast-moving air on a motorcycle, the motor can rely on the air to help cool the engine rather than having a separate sump for coolant.
There are some similarities to motorcycle oil and car motor oil in that it’s better when both have additives to protect the engine from premature wear, oxidation, gunk and deposits, overheating, and friction—so they do have some things in common. However, it’s important to keep in mind that selecting an automotive motor oil for your motorcycle might work in a pinch, but over time it can cause damage to your gears and result in gear failure.
What to Look for in a Motorcycle Oil
With a motorcycle oil, it really is generally best to go with a full synthetic or a synthetic blend over conventional mineral oil motor oil, as synthetics have been optimized to run on the smaller, hotter, and faster engine on your bike. You’ll need to find a motorcycle oil that is capable of:
· Running at a higher temperature than regular
· Offering higher viscosity than car motor oil
· Offering lower oil burn-off or volatility than regular motor oil
· Reducing gunk and deposits from forming in the engine
· Acting as a lubricant for all the moving parts on your bike, including the gearbox
Wet Sump vs. Dry Sump Engines
A wet sump engine relies on a larger oil pain with a single oil pump to distribute the oil. Dry sump engines, on the other hand, tend to have shallower oil pans with sometimes more than two oil pump systems leading to a separate reservoir. So which type of sump is on your new bike?
By and large, Harley Davidsons have dry sump engines—which is why the oil typically can be found under the seat rather than under a spinning crank of the engine. The benefit of the dry sump system on your bike is that it offers a higher valve area in each cylinder which allows for more air and fuel flow within the cylinder. This means shorter strokes, which allows for higher revving, which means more torque and best of all, more power.
While a dry sump engine at a first glance might seem like a more complicated means of lubricating the engine, the benefits of this type of sump system are part of what makes riding your Harley such an enjoyable experience. Aside from the fun associated with higher revving and more motor power, there are also safety benefits to these features as well, including increased maneuverability in potentially dangerous traffic situations.
What Do I Do With Used Engine Oil?
Ready to have your Harley serviced or change your own motor oil? You might be wondering, how does one dispose of used engine oil? The answer to this is to pour your spent oil back into the empty oil container from your fresh oil, cap it off, and bring it with you to a service station, quick lube shop, or participating auto parts store with a motor oil collecting reservoir. Fortunately, motor oil technology has come such a long way since its “invention” in the late 1800s that we can now refine and recycle used oil so that it may be used over and over again rather than polluting the environment or ending up in a landfill.
What's the Best Harley Davidson Engine Oil?
Alright, so let’s cut to the chase—which Harley Davidson engine oil is best? Most mechanics, motorcycle enthusiasts, and Harley dealers will recommend a full synthetic engine oil for your bike to keep things running in tip-top condition; but if you have any doubts at all about what the best motorcycle oil is for your particular model, refer to your owner’s manual for indications of preferred weights and viscosities.
When it comes time to choose the right motorcycle oil for your next oil change, it’s important to choose an American Automobile Association (AAA) tested brand you can trust. AMSOIL 20W-50 Synthetic Motorcycle Oil is one of the number one recommended motorcycle lubricants for Harley Davidson bikes, though it also works great for BMW, Ducati, and Triumph as well.
Are you ready to get the most out of your engine performance while protecting it from undue wear? Browse the AMSOIL catalogue of high-quality motorcycle-specific engine lubricants today!