If the engine is the heart of your motorcycle, then oil is its lifeblood.
When it comes to engine oil, there are a lot of opinions, myths, superstitions, and voodoo out there. It’s your bike, you can do what you want, and we have plenty of good ol’ dino juice that’ll do a fine job keeping your motorcycle engine humming along for miles to come, but here at J&P Cycles, we’re fans of high-end synthetic engine oils in general, and Motul in particular. There are a ton of good reasons to use something like Motul oil in your engine, and with a little help straight from the crew at Motul, we put together the top five reasons you should be running a high-end synthetic oil in your motorcycle.
Before we dive into the why, let’s define what we really mean by a high-end synthetic oil. In the case of the 100% synthetic oils that Motul makes, we’re looking at oils composed of a 100% synthetic group V ester base stock. What does that mean? Without going too deep into the chemistry rabbit hole, the base stock of an oil is determined by the oil’s composition, refining method, and certain critical properties like viscosity index, and sulfur, and saturated compound (compounds which resist certain reactions, like oxidation) content. The important thing to know for our purposes here is that group I through group III oils are petroleum-based oils, and group IV and V are synthetic. The difference between group IV and V being that group IV oils are specifically oils based on poly-alpha-olefin (PAO) polymers, and group V oils are pretty much any other synthetic oil (such as an ester-based oil) that is neither petroleum nor PAO-based. Esters have a significant advantage in that they can be synthesized, formulated, and blended to provide very specific - and consistent - behaviors. Now that we have a good idea of what we mean when we’re talking about a high-end oil, let’s get into the top five benefits.
- They’re strong and durable. Ester synthetic oils can provide up to five times higher shear and film strength than other oils. Shear strength is the resistance of the oil to a loss in viscosity when subjected to mechanical stress in the engine (such as being pressed up between the a hot and fast-moving piston and the cylinder walls of an engine). Film strength is the resistance of the oil to breaking or separating under pressure, and is the oil’s ability to lubricate and lessen the effects of metal on metal contact in the engine. This means the oil won’t wear out as easily, and will retain its ability to provide the same lubrication performance across its entire life.
- Due to their strong chemical bonds, synthetic oils can withstand the extremely high running temps generated by big air cooled motors.
- Ester synthetic oils contain the strongest polymers and additives. They can survive the recommended oil change intervals requested by Harley-Davidson (and other manufacturers). For your Harley, this means 5,000 miles for the engine, 10,000-15,000 in the primary case and 20,000 in the transmission.
- Being high in saturated compounds means a Motul ester synthetic will fight oxidation much better then cheaper synthetic and conventional oils. This combined with the higher shear and film strength and ability to withstand high temp means they’ll continue to easily flow through the engine and keep it clean after thousands of miles
- High-end synthetic oils that meet the requirements set by Harley-Davidson can be used in all three compartments. That means they’ll provide good clutch grip, prevent gear wear, withstand extreme temps, protect engine, and last for the recommended miles no matter where you use them.
So, while a high-end oil like an ester synthetic from Motul may cost more and seem like a needless luxury, at the end of the day, it’ll protect all components of your engine better and for longer than cheaper synthetics and conventional oils. Your engine in turn will last longer and perform better. Oil is cheaper than engine repairs, so we think the few extra bucks for primo oil is more than worth it.