Home » Bikes » Running » Harley Davidson Engine Oil Selector

Harley Davidson Engine Oil Selector

harley davidson recommended motorcycle engine oil - Harley Davidson Engine Oil Selector

This guide is designed to help you find the best oil for your Harley. While H-D supply their own oil, you definitely don’t have to use it to ensure your Harley runs smoothly.

The chart below shows you the recommended engine oil and the amount of oil you need for each model.

The chances are, your recommended oil will be 20W50 as that’s the most common grade for Harleys. Whether you’re running a 103, a Twin Cam or a Softail and whether you run Synthetic or Regular oil, the right oil will make all the difference.

In air-cooled engine (like the ones found in most Harleys), heat can be an issue. That’s why it’s often better to choose a synthetic-based oil over a mineral (regular) oil as it’ll have better heat tolerance .

With our oil selector, you’ll be able to choose a premium oil but save a few quid on the official Harley engine oil.

We have researched the right oil to the best of our ability but it goes without saying: always consult your owner’s manual where you will find the manufacturer’s recommended engine oil.

Table of Contents

Harley Engine Oil Chart

The recommended engine oil for all Harley Davidson models.

MakeModelEngine oilOil Capacity
HARLEY-DAVIDSONBREAKOUT20W503.1 – 3.3 L
HARLEY-DAVIDSONBREAKOUT (EURO 4)20W503.1 – 3.3 L
HARLEY-DAVIDSONBREAKOUT PRO STREET20W503.1 – 3.3 L FS
HARLEY-DAVIDSONCVO ROAD GLIDE CUSTOM20W50 FS3.8 L
HARLEY-DAVIDSONCVO SOFTAIL CONVERTIBLE20W50 FS3.3 L SYN3
HARLEY-DAVIDSONCVO SOFTAIL DELUXE20W503.8 L FS
HARLEY-DAVIDSONCVO STREET GLIDE20W503.8 L FS
HARLEY-DAVIDSONCVO STREET GLIDE (114 CUI)20W50 S4.9 L
HARLEY-DAVIDSONCVO STREET GLIDE (117 CUI)20W50 SYN34.9 L
HARLEY-DAVIDSONDUO GLIDE (PANHEAD)50W3.6 – 3.8 L
HARLEY-DAVIDSONDYNA FAT BOB20W502.5 L
HARLEY-DAVIDSONDYNA FAT BOB20W502.5 L
HARLEY-DAVIDSONDYNA FAT BOB20W502.5 L
HARLEY-DAVIDSONDYNA FAT BOB (EURO 4)20W502.8 L
HARLEY-DAVIDSONDYNA GLIDE CONVERTIBLE20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER20W502.5 L
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER20W502.5 L
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER (EVOLUTION)20W502.5 – 2.8 L
HARLEY-DAVIDSONDYNA GLIDE LOW RIDER (TWIN CAM)20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA LOW RIDER20W502.8 L
HARLEY-DAVIDSONDYNA LOW RIDER (EURO 4)20W502.8 L
HARLEY-DAVIDSONDYNA LOW RIDER S20W50 FS2.8 L
HARLEY-DAVIDSONDYNA STREET BOB20W502.5 L
HARLEY-DAVIDSONDYNA STREET BOB20W502.5 L
HARLEY-DAVIDSONDYNA STREET BOB20W502.9 L
HARLEY-DAVIDSONDYNA STREET BOB (EURO 4)20W502.8 L
HARLEY-DAVIDSONDYNA SUPER GLIDE20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA SUPER GLIDE20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOM20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOM20W502.5 L
HARLEY-DAVIDSONDYNA SUPER GLIDE CUSTOM 2.9 L
HARLEY-DAVIDSONDYNA SUPER GLIDE SPORT20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA SUPER GLIDE T-SPORT20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA SWITCHBACK20W502.5 L
HARLEY-DAVIDSONDYNA SWITCHBACK20W502.5 L
HARLEY-DAVIDSONDYNA WIDE GLIDE20W502.5 L
HARLEY-DAVIDSONDYNA WIDE GLIDE20W502.5 L
HARLEY-DAVIDSONDYNA WIDE GLIDE20W502.5 L
HARLEY-DAVIDSONDYNA WIDE GLIDE (EURO 4)20W502.8 L
HARLEY-DAVIDSONDYNA WIDE GLIDE (EVOLUTION)20W502.6 – 2.8 L
HARLEY-DAVIDSONDYNA WIDE GLIDE (TWIN CAM)20W502.6 – 2.8 L
HARLEY-DAVIDSONE/EL KNUCKLEHEAD (61 CUI/OHV)50W3.8 L
HARLEY-DAVIDSONELECTRA GLIDE ULTRA CLASSIC 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE 1200 (SHOVELHEAD)50W3.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE 1340 (SHOVELHEAD)50W3.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE CLASSIC20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE CLASSIC20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE STANDARD20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE STANDARD20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE STANDARD20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA CLASSIC (TWIN CAM)20W503.6 – 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA LIwithED/LOW 3.8 L
HARLEY-DAVIDSONELECTRA-GLIDE ULTRA LIwithED/LOW 4.75 L
HARLEY-DAVIDSONFAT BOY (EVOLUTION)20W502.6 – 2.8 L
HARLEY-DAVIDSONFAT BOY (TWIN CAM)20W503.1 – 3.3 L
HARLEY-DAVIDSONFAT BOY INJECTION (TWIN CAM)20W503.1 – 3.3 L
HARLEY-DAVIDSONFAT BOY S20W50 FS3.3 L
HARLEY-DAVIDSONFAT BOY/FAT BOY SPECIAL (FLSTFB)20W503.1 – 3.3 L
HARLEY-DAVIDSONFAT BOY/FAT BOY SPECIAL (FLSTFB)20W503.1 – 3.3 L
HARLEY-DAVIDSONFAT BOY/FAT BOY SPECIAL (FLSTFB)20W503.1 – 3.3 L
HARLEY-DAVIDSONFORTY-EIGHT20W502.6 – 2.65 L
HARLEY-DAVIDSONFORTY-EIGHT20W502.6 – 2.65 L
HARLEY-DAVIDSONFORTY-EIGHT (EURO 4)20W502.65 L
HARLEY-DAVIDSONFREEWHEELER (EURO 4) 4.9 L
HARLEY-DAVIDSONFX 1200 SUPER GLIDE/FAT BOB50W3.6 – 3.8 L
HARLEY-DAVIDSONFX 1340 SUPER GLIDE/WIDE GLIDE50W3.6 – 3.8 L
HARLEY-DAVIDSONFXR SUPER GLIDE20W502.6 – 2.84 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC20W502.6 – 2.84 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONHERITAGE SOFTAIL CLASSIC (EURO 4)20W503.1 – 3.3 L
HARLEY-DAVIDSONHERITAGE SOFTAIL SPECIAL/NOSTALGIA20W502.6 – 2.8 L
HARLEY-DAVIDSONHERITAGE SPRINGER20W503.1 – 3.3 L
HARLEY-DAVIDSONHYDRA GLIDE (PANHEAD)50W3.8 – 3.8 L
HARLEY-DAVIDSONLIVEWIRE  
HARLEY-DAVIDSONNIGHT ROD20W504.2 L
HARLEY-DAVIDSONNIGHT ROD SPECIAL20W504.2 L
HARLEY-DAVIDSONNIGHT ROD SPECIAL 4.5 – 4.7 L
HARLEY-DAVIDSONNIGHT ROD SPECIAL/ABS20W504.1 – 4.3 L
HARLEY-DAVIDSONROAD GLIDE (107 CUI) 4.9 L
HARLEY-DAVIDSONROAD GLIDE SPECIAL20W503.8 L
HARLEY-DAVIDSONROAD GLIDE SPECIAL (EURO 4)20W504.9 L
HARLEY-DAVIDSONROAD GLIDE ULTRA 3.8 L
HARLEY-DAVIDSONROAD GLIDE ULTRA (EURO 4)20W504.75 L
HARLEY-DAVIDSONROAD KING20W503.6 – 3.8 L
HARLEY-DAVIDSONROAD KING20W503.6 – 3.8 L
HARLEY-DAVIDSONROAD KING (EURO 4) 4.9 L
HARLEY-DAVIDSONROAD KING (TWIN CAM)20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING CLASSIC20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING CLASSIC20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING CLASSIC 3.8 L
HARLEY-DAVIDSONROAD KING CLASSIC (EURO 4) 4.9 L
HARLEY-DAVIDSONROAD KING CLASSIC (TWIN CAM)20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING CUSTOM20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING CUSTOM20W503.5 – 3.8 L
HARLEY-DAVIDSONROAD KING SPECIAL (EURO 4) 4.9 L
HARLEY-DAVIDSONROCKER20W503.1 – 3.3 L
HARLEY-DAVIDSONROCKER C20W503.1 – 3.3 L
HARLEY-DAVIDSONSEVENTY-TWO20W502.6 – 2.65 L
HARLEY-DAVIDSONSOFTAIL BAD BOY20W502.6 – 2.8 L
HARLEY-DAVIDSONSOFTAIL BLACKLINE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL BREAKOUT (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL BREAKOUT (114 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL CROSS BONES20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL CUSTOM20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL CUSTOM (EVOLUTION)20W502.6 – 2.8 L
HARLEY-DAVIDSONSOFTAIL DELUXE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL DELUXE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL DELUXE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL DELUXE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL DELUXE (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL DEUCE20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL FAT BOB (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL FAT BOB (114 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL FAT BOY (107 CUI)20W50 S4.7 L
HARLEY-DAVIDSONSOFTAIL FAT BOY (114 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL FXDR (DESTROYER) 114 CUI20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL HERITAGE CLASSIC (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL HERITAGE CLASSIC (114 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL HERITAGE SPRINGER20W502.6 – 2.8 L
HARLEY-DAVIDSONSOFTAIL LOW RIDER (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL LOW RIDER S (114 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL NIGHT TRAIN20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL NIGHT TRAIN (EVOLUTION)20W502.6 – 2.8 L
HARLEY-DAVIDSONSOFTAIL NIGHT TRAIN (TWIN CAM)20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL SLIM20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL SLIM (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL SLIM (EURO 4)20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL SLIM S20W50 FS3.3 L
HARLEY-DAVIDSONSOFTAIL SPORT GLIDE (107 CUI)20W50 S4.75 L
HARLEY-DAVIDSONSOFTAIL SPRINGER (EVOLUTION)20W502.6 – 2.8 L
HARLEY-DAVIDSONSOFTAIL SPRINGER (TWIN CAM)20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL SPRINGER CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL SPRINGER CLASSIC20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL STANDARD20W503.1 – 3.3 L
HARLEY-DAVIDSONSOFTAIL STREET BOB (107 CUI)20W50 S4.7 L
HARLEY-DAVIDSONSPORT GLIDE (FXRT)20W502.6 – 2.84 L
HARLEY-DAVIDSONSPORTSTER 1000 (XLH/XLT/XLS/XLX)2-Stroke Ext Tank2.84 – 3.8L
HARLEY-DAVIDSONSPORTSTER 110020W502.5 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 120020W502.6 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM20W502.6 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM (EURO 4)20W502.6 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM20W502.65 L
HARLEY-DAVIDSONSPORTSTER 1200 CUSTOM20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 IRON20W502.6 L
HARLEY-DAVIDSONSPORTSTER 1200 LOW20W502.65 L
HARLEY-DAVIDSONSPORTSTER 1200 NIGHTSTER20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 ROADSTER20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 ROADSTER (EURO 4)20W502.65 L
HARLEY-DAVIDSONSPORTSTER 1200 SPORT20W502.6 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 1200 SUPER LOW20W502.6 – 2.65 L
HARLEY-DAVIDSONSPORTSTER 1200 SUPER LOW (EURO 4)20W502.65 L
HARLEY-DAVIDSONSPORTSTER 883 DELUXE20W502.5 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 883 HUGGER20W502.5 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 883 IRON20W502.65 – 2.84 L
HARLEY-DAVIDSONSPORTSTER 883 IRON (EURO 4)20W502.6 L
HARLEY-DAVIDSONSPORTSTER 883 R20W502.6 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 883 R ROADSTER20W502.6 – 2.84 L
HARLEY-DAVIDSONSPORTSTER 883 STANDARD/DELUXE20W502.5 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 883 SUPERLOW20W502.6 L
HARLEY-DAVIDSONSPORTSTER 883 SUPERLOW (EURO 4)20W502.6 L
HARLEY-DAVIDSONSPORTSTER 883/LOW20W502.6 – 2.8 L
HARLEY-DAVIDSONSPORTSTER 900 (XLH/XLCH)50W2.84 – 2.84 L
HARLEY-DAVIDSONSPORTSTER CUSTOM 5320W502.5 – 2.8 L
HARLEY-DAVIDSONSPORTSTER CUSTOM 53/CUSTOM20W502.6 – 2.84 L
HARLEY-DAVIDSONSTREET 750 3.1 L
HARLEY-DAVIDSONSTREET 750 (EURO 4) 3.1 L
HARLEY-DAVIDSONSTREET GLIDE20W503.6 – 3.8 L
HARLEY-DAVIDSONSTREET GLIDE20W503.6 – 3.8 L
HARLEY-DAVIDSONSTREET GLIDE 3.8 L
HARLEY-DAVIDSONSTREET GLIDE (107 CUI) 4.9 L
HARLEY-DAVIDSONSTREET GLIDE SPECIAL 3.8 L
HARLEY-DAVIDSONSTREET GLIDE SPECIAL (107 CUI) EURO 4 4.9 L
HARLEY-DAVIDSONSTREET GLIDE SPECIAL (114 CUI) 4.9 L
HARLEY-DAVIDSONSTREET ROD20W504.2 L
HARLEY-DAVIDSONSTREET ROD 750 (EURO 4) 3.1 L
HARLEY-DAVIDSONTRI GLIDE ULTRA 3.8 L
HARLEY-DAVIDSONTRI GLIDE ULTRA (EURO 4) 4.75 L
HARLEY-DAVIDSONV-ROD (A-MODELL)20W504.2 L
HARLEY-DAVIDSONV-ROD (B-MODELL)20W504.0 – 4.2 L
HARLEY-DAVIDSONV-ROD / ABS20W504.2 L
HARLEY-DAVIDSONV-ROD 10TH ANNIVERSARY 4.5 – 4.7 L
HARLEY-DAVIDSONV-ROD MUSCLE20W504.1 – 4.3 L
HARLEY-DAVIDSONV-ROD MUSCLE 4.5 – 4.7 L
HARLEY-DAVIDSONXLCR CAFE RACER50W2.6 – 2.9 L
HARLEY-DAVIDSONXR 1000 (SPORTSTER)20W502.6 – 2.9 L
HARLEY-DAVIDSONXR 120020W502.65 – 2.84 L
HARLEY-DAVIDSONXR 1200 X20W502.65 – 2.84 L

What You Need To Know

If you better understand the differences between different engine oils, you’ll always pick the best one for your needs and budget.

What’s the difference between different engine oils?

Mineral oils are refined from petroleum, but even mineral oils contain some synthetic compounds or additives to improve them. Semi-synthetic oils are a blend of mineral and synthetic oils. They have definite improvements over pure mineral oils. Semi-synthetics can contain “hydrocracked” bases.

Hydrocracked oils are mineral oils that have been subjected to intense pressure and temperature to change the structure of the molecules, making the resultant oil more stable and resistant to evaporation at higher temperatures. Semi-synthetic oils don’t cost much more than mineral oils do, but offer advantages over the latter.

Full-synthetic oils, however, are far more expensive than mineral or semi-synthetic oils.  Full-synthetics are man-made oils that have been tailored to give them certain advantages like the fact that they perform better in extreme temperatures, are less likely to evaporate or thin excessively in heat, etc. Full-synthetics contain poly-alpha-olefins (PAO) and esters. PAOs don’t gel at low temperatures, making them necessary for any true 0W oil.

Esters are similar to PAOs but also help protect metal surfaces and offer good lubrication. Full-synthetic oils are expensive and, unless you are racing, not necessarily recommended for motorcycles. For the everyday rider, a semi-synthetic shear-stable 10W-40 oil with some ester content would be a great choice.

What’s the best type of oil to use for road riding?

Your ideal choice of oil would be an ester semi-synthetic 10W-40 or a 10W-30 that is also shear-stable. The fact that the oil is shear-stable is more important than the fact that it is semi-synthetic.

You are still better off choosing shear-stable mineral-based oil than a low-quality semi-synthetic one that isn’t shear-stable. Only for frequent long-distance riders would the cost of a full-synthetic oil be worth it, as it can help save on oil changes and fuel costs. 

Does a high-performance oil produce more power?

There will always be loss of engine output due to things like thermodynamics, which can’t be changed that much. However, some of that loss, about 6%, is due to oil drag. By using quality but low viscosity oil, this loss can be minimised and engine power increased. For a typical 100bhp motorcycle, a lighter engine oil might show a 2bhp peak improvement.

Choosing the right oil filter

If you’re changing your engine oil, it makes sense to change the oil filter too. An oil filter removes tiny particles from the oil, helping to keep the oil fresher and work to its best ability for longer. A new filter costs a few quid and it only takes a couple of minutes to change. 

We’ve put together this Harley-Davidson oil filter chart to help you pick the best oil filter for your motorcycle.

How To Change Your Motorcycle’s Oil

how to change motorcycle engine oil - Harley Davidson Engine Oil Selector

If you’ve never changed your motorcycle’s oil before, you might be apprehensive but you needn’t be. With the right tools, anyone can change their engine oil in under an hour. We’ve put together this simple guide to help you through your first motorcycle oil change.

Recommended Motorcycle Engine Oils 

The table below shows all the different engine oils available for your Harley Davidson engine. We’ve listed the best motorcycle engine oil available, from Mineral-based engine oils to Semi-Synthetic, right up to Fully Synthetic,  top-quality ester-based oils.

The table has been compiled from owner reviews and ratings and manufacturer-specified oil, where applicable.

silkoline v twin 20w50 cruiser engine oil - Harley Davidson Engine Oil Selector
20W50

Mineral based. Mineral oil based 4-stroke engine oil for all Harley Davidson & Metric V-Twin Cruisers. Provides protection over a wide range of operating conditions. Promotes a high level of engine cleanliness.

putoline formula v twin 20w40 - Harley Davidson Engine Oil Selector
20W40

Semi Synthetic. Four stroke engine oil is ideal for Harley engines. Exceeds the requirements of the manufacturer. Offers excellent high mileage engine protection.

motul 20w50 fully synthetic motorcycle engine oil - Harley Davidson Engine Oil Selector
20W50

Fully Synthetic. This is the best quality oil Harley engine oil. 100% synthetic 4-Stroke lubricant with Ester technology. Engineered for 2 cylinder engines and meets Harley Davidson spec. Meets JASO MA2 specifications for optimal wet clutch performance and suitable for catalytic converters.

What does Engine Oil Do?

A good engine oil lubricates, protects, cleans, and cools the engine to keep it running smoothly.

Engine oil provides lubrication between the individual engine components, reducing friction. It does so by providing a slippery film between the moving parts in the running engine. This ensures that the engine can run efficiently, at optimal performance and with increased power. Lubrication is also vitally important at start-up. Here, the cold oil in the oil sump needs to be quickly pumped back into the engine so that it can provide lubrication. This allows for an ideal cranking speed to turn over the engine. In order to ensure that that oil can flow quickly at start-up, but also provide enough of a film to protect the engine when running, an engine needs an oil with different viscosity ranges.

Engine oil creates a film on moving parts in the engine, which acts as a protective layer. By preventing and minimising metal-to-metal contact, wear of these components is reduced. Engine oil has another way it protects the engine. Combustion by-products, oxidation and contamination from condensation all form acids. If left unchecked, these acids can cause corrosion in the engine, which can lead to components failing. Engine oil ensures that this does not happen and so protects the engine.

For an engine to run optimally, it needs to be clean. Deposits in the engine can gum it up and reduce its performance. Further, unnecessary wear and damage in an engine can be caused by microscopic contaminants.  For perspective, a single hair is 100 microns thick. Contaminants as small as 5 to 20 microns could easily cause damage to an engine. Engine oil keeps the engine clean by holding these contaminants in suspension until they can be removed via the oil filter. Engine oil also prevents damaging deposits from forming.

Finally, engine oil also helps to keep the engine cool. Heat is caused by the friction between the moving parts as well as by combustion. The radiator is responsible for cooling the top part of the engine. Cooling the rest of the engine, like the pistons, rod bearings, timing gears, crankshaft, camshaft etc., is up to engine oil. As oil passes over these heated surfaces, it absorbs the heat. This hot oil then travels to the oil sump, where it is cooled by the air surrounding it.

 

What is Multigrade Oil?

different motorcycle engine oils guide 488x305 - Harley Davidson Engine Oil Selector

Oil is thick and viscous when it is cold and then thins as it warms up.  Cold thick oil struggles to circulate as the engine is started, but using a thinner oil here would mean that, once heated, the oil would be too thin to adequately protect the engine.

The answer is using a multigrade oil. This oil, due to the addition of polymer, has two different viscosity grades.  By adding a polymer to a thin oil base, it is possible to have an oil that performs well in both hot and cold conditions. The polymer ensures that as the oil is heated, the rate of thinning is slowed down. It also ensures that, as the oil cools, the rate of thickening is slowed too.

Multigrade oil is identifiable by its two numbers, say 10W-40. The first number 10W (W stands for Winter) refers to the viscosity of the oil at a low temperature. A lower number would mean a thinner oil, so a 5W would be thinner than a 10W. A 0W oil would be the thinnest at cold temperature.

The second number, 40, refers to the viscosity of the oil at a high temperature, which will always be measured at 100 °C. Again, a lower number means a thinner oil, so, at 100 °C, a 30 oil would be thinner than the 40 oil. It is, of course, important to follow the guidelines of the manufacturer in choosing the correct multigrade oil for your motorcycle.

Synthetic Engine Oils Common Questions

We’ve answered some of the most common questions when it comes to synthetic motorcycle engine oil.

Will my engine consume more synthetic oil?

Not likely.  In modern engines, most oil consumption happens due to evaporation at high temperatures. Synthetic oils, however, tend to be far more resistant to evaporation, especially if they contain ester and PAO, so oil consumption should be lower with a synthetic. Irrelevant of oil type, oil consumption will go up in engines with defective seals, and worn valve guides and piston rings. Here, one might as well use a cheaper oil instead of a synthetic one.

Is synthetic oil compatible with other engine oil?

Synthetic oil is fully compatible with any other engine oil. Provided the oil is for a 4- stroke engine, one can safely mix any type of oil irrelevant of what its base is or what it contains, be it mineral, semi-synthetic, hydrocracked synthetic, PAO, ester, etc. The exception here would be Castor-oil-based racing oils.

Will a synthetic oil void my warranty?

As long as you follow the instructions in your handbook in regards to the viscosity ranges and API of an oil, you can use whichever oil you choose, including synthetics, without affecting your warranty. The choice of brand is also up to you as OEMs, by law, cannot prescribe this.

Are synthetic oils worth the extra cost?

This depends. For a great bike in a great condition, the right synthetic oil will help keep maintenance costs down, lower fuel costs, and keep it running like new.  For an oil-guzzling older model, synthetic oils may just not be worth the price.

Motorcycle Engine Oil FAQ

Can I use car engine oil in my motorcycle?
This can be risky. Even though you can and will find car oil with the same viscosity ratings (i.e. 10w40) as for motorcycle engines, the additives in the oil will be different. Most cars use a separate gearbox oil and most cars have a dry clutch. So a car oil could make your clutch slip or knacker your gearbox. If you're buying a bike that's been run on car oil, beware!

Does engine oil have an expiry date?
Engine oils have an expiry date which means the performance levels can no longer be guaranteed. However if your oil hasn't been opened, it'll take years and years for it to degrade. If your oil has been opened and is a couple of years out of date, it'll most likely be absolutely fine. However, if you've already opened it and it's 5 years out of date you'll be better off buying fresh oil as the additives in the oil may have oxidised and lost their qualities.

What are the most critical areas where the oil flows?
For a motorcycle engine, the critical engine areas are the piston assembly, bearings and valve train. The engine oill also lubricates the clutch (but not if your motorcycle has a dry clutch) and your motorcycle's gearbox.

What does my oil filter do and do I need to replace it?
The oil filter traps foreign particles and debris that are introduced into the oil by normal riding. These particles can be anything from carbon deposits to small metal particles from your motorcycle's engine. These particles can lead to engine damage, while a blocked filter may lead to oil starvation and ultimately engine failure. An oil filter costs just a few pounds, so it makes sense to change this every time you do an oil change.

What is the difference between a mineral, semi-synthetic, and full-synthetic engine oil?
Mineral oils are refined from petroleum, but even mineral oils contain some synthetic compounds or additives to improve them. Semi-synthetic oils are a blend of mineral and synthetic oils. They have definite improvements over pure mineral oils. Semi-synthetics can contain “hydrocracked” bases. Hydrocracked oils are mineral oils that have been subjected to intense pressure and temperature to change the structure of the molecules, making the resultant oil more stable and resistant to evaporation at higher temperatures. Semi-synthetic oils don’t cost much more than mineral oils do, but offer advantages over the latter.

Why does a 2-stroke oil have to be mixed with fuel?
A 2-stroke engine is built and runs differently to a 4-stroke one. A 4-stroke engine keeps most of its oil in its crankcase and oil sump and recirculates this oil to lubricate the engine. With a 2-stroke engine, the process is somewhat different. Here, there is no oil sump as the crankcase deals with the compression and induction of the fuel/air mix. The only way, therefore, to provide oil to the engine for lubrication is by adding it to the fuel. As this oil is burnt with the fuel, it can’t be recirculated. A specific 2-stroke oil is needed as 4-stroke oil would leave damaging deposits behind when it burns.

Is any engine oil better than no engine oil?
Yes, but when it comes to motorcycles, the 'right' engine oil is better than 'any' engine oil!

Why do some engines burn oil?
Unfortunately, some types of engines just use more oil than others due to their design. Here, the burnt oil can leave damaging deposits behind, meaning these engines often need more top overhauls. However, if a touring engine uses more oil than is necessary, changing to a lighter grade of oil often solves the problem.

Can I top up my engine with a different type of oil?
As long as you don’t mix a 2-stroke oil with a 4-stroke oil, you can safely top your engine up with a different type of oil. You probably wouldn’t want to mix different grades, say, a 5W-30 synthetic with a 20W-50 mineral oil, but if you do, it likely wouldn’t do any harm.

Do I need to warm up my engine before riding?
The oil needs to be warm, but, even better, hot, especially when riding at speed. When cold oil is pumped into an engine, cavitation (bubbles of vacuum within the oil) is likely to occur. This, in essence, means that the engine does not receive enough oil for it to run optimally at speed. Warmer, and so thinner, oil ensures that the engine not only receives enough oil, but that all moving parts within it can work optimally. Ideally, use a 5W-40 or 10W-40 oil and ensure the engine warms up properly for a few km before speeding up.

Do I need to regularly change my oil?
If you tend to drive short distances with a low annual mileage, regular oil changes are vital, irrelevant of whether the minimum mileage for an oil change was reached or not. Water vapour and fuel tend to make their way into the oil, and, unless you drive long distances, they never have the chance to evaporate. This can cause damages like corrosion, gear tooth pitting, and ring and bore wear. Long-distance riders with a high annual mileage who use a high-quality oil can afford to be a little more relaxed on the oil changes.

What's the best type of oil to use in a road bike?
Your ideal choice of oil would be an ester semi-synthetic 10W-40 or a 10W-30 that is also shear-stable. The fact that the oil is shear-stable is more important than the fact that it is semi-synthetic. You are still better off choosing shear-stable mineral-based oil than a low-quality semi-synthetic one that isn’t shear-stable. Only for frequent long-distance riders would the cost of a full-synthetic oil be worth it, as it can help save on oil changes and fuel costs.

How does oil 'cling' onto the engine's internals?
Where there is high-speed rotation in the engine, e.g. with a plain bearing, the high speed draws a thick layer of oil between the two surfaces, like a wedge. Here, this oil supports and carries the load of these surfaces. As soon as the spinning stops, however, either due to the slowing down or stopping of the engine, this wedged oil gives way. Where no rotation occurs in an engine, oil cannot form this thick wedged layer to protect metal surfaces. Here, oil provides a thin protective film and often relies on anti-wear agents, detergents, and anti-oxidant chemicals to help protect from metal-to-metal contact.

Engine Oil Glossary

When it comes to motorcycle engine oil, there are a lot of terms that get thrown around. We’ve created this quick glossary to help you understand what everything means.

Anti-Wear Agent
In boundary lubrication conditions, this additive reduces the amount of wear caused by metal-to-metal contact by chemically reacting with the metal surfaces and forming a film between them.

Corrosion Inhibitor
This engine oil additive helps to protect metal surfaces by inhibiting corrosion caused by contaminants. It usually does so through a chemical reaction that forms a protective film over the metal surfaces.

Detergent
This engine oil additive chemically reacts with acidic, sludge-forming contaminants in the oil to neutralise them. It then holds these, now harmless, impurities in suspension.

Hydrocracking
Using hydrogen, the hydrocarbons in mineral oil are put under high temperature and pressure to crack their molecules. The result is a synthetic-like base stock of high quality. When blended with further additives, hydrocracked oil is not only extremely stable but also comparable in performance to synthetic oils.

Oxidation inhibitor
This additive prolongs the storage life of engine oil. It does so by helping to counteract the negative effects of oxidation.

Synthetic lubricant
The base oils for synthetic lubricants are artificially made from chemical compounds or polymerisation of hydrocarbons, instead of by refining petroleum. Synthetic oils offer several advantages over mineral oils.

Viscosity
Viscosity refers to a fluid’s resistance to flow. Temperature directly impacts the viscosity of the oil. Cold oil is thicker and hot oil is thinner.  An engine oil, however, needs to be able to adequately protect and lubricate an engine both at start-up, when it is cold and while running, when it is hot. The solution here is an oil with two different viscosity grades, i.e. a multigrade oil.

Questions? Tips, Errors?

We work hard to keep our motorcycle oil chooser up to date but if you spot any errors or you can help us fill out any missing info, we’d love to hear from you. Likewise, if you have a question, just enter it in the comments box below and we’ll get back to you straight away. Thank you!

>
Scroll to Top