Best Synthetic Motorcycle Oil Review

Synthetic motorcycle oil – this is a huge market and very competitive as there are just so many brands & claims. Plus, bikers are so much closer, touchier and feelier with their bikes and what they buy, modify and use, it is a much more personal decision & choice.

Yes, I’ve got a bike too and ride and share with many our experiences. I am very close to my bike and only want the best. Here I can share with you the top rated synthetic motorcycle oil available in the market.

The Best Synthetic motorcycle Oil


Brand & Product Name



Lucas High Performance



Royal Purple Max-Cycle



Castrol Power1 4T



Castrol Power1 V-Twin



Mobil 1 Racing 4T



Mobil 1 V-Twin



Before considering whether to use conventional or synthetic oil in your engine, be sure you are using an oil with the correct grade and service rating for your motorcycle.

The Authority

The American Petroleum Institute (API) and the Japanese Engine Oil Standards Implementation Panel (JASO) set standards for engine oils, ensuring that they meet original equipment manufacturer (OEM) requirements. The best synthetic motorcycle oils meet or exceed these standards and the requirements for most modern bikes.


As a start, you still should rely on the API and SAE recommendations from the manuals for your specific bike.

However, if you want to go Full Synthetic and want to know more why you should use synthetic oil or what are the benefits, you can check out our article What is the best synthetic oil?.

Oil change is the most important thing that a person can do for their motorcycle. It does not cost a lot of money, but it saves a lot in repairs if not done regularly.

With this in mind, synthetic oil is one of the best investments that a motorcycle owner can make. 

Synthetic Motor Oil and Motorcycles

Additives and Clutch Slippage

Motorcycle-specific oils contain additives just like automotive oils do. The difference is that motorcycle oil has additives designed to work specifically in the extreme conditions found in high-revving motorcycle engines, while automotive oil is designed for relatively low-revving engines. High revs call for an oil that tolerates high-sheer forces. Motorcycles with wet clutches also have their own needs.

Cars and some motorcycles (like Harley Davidsons) have separate reservoirs for engine and transmission oils. Automotive oils designed for car engines often contain additives meant to improve fuel mileage, which is specified on the bottom of the API seal with the term “Energy Conserving.”  

These additives can cause wet clutches to slip during shifting. Many oil companies now make motorcycle-specific oils, without these additives, that are engineered specifically for wet-clutch bikes. 


  "Before considering whether to use conventional or synthetic oil in your engine, be   sure you are using an oil with the correct grade and service rating for your motorcycle."

Synthetic vs. Conventional Oil

Synthetic oil and conventional oil are both composed of long-chain hydrocarbons. Both are refined to produce the most uniform molecules of hydrocarbons possible, but synthetic oils go through polymerization and distilling processes beyond those of conventional oils.

The hydrocarbons are cracked during refining, and/or rebuilt resulting in molecules of more uniform shape and size than those comprising conventional oil. Hence, synthetic oil flows better at low temperature, and it usually retains its viscosity much better at high temperatures.

Your motorcycle’s manual specifies a recommended oil change interval, and few if any are as low as the 3000 miles most oil companies recommend. However, the best synthetic motorcycle oils can last 10,000 miles or more, even under the harsh conditions that high-performance engines produce.

Conventional oils break into smaller hydrocarbon chains much faster than synthetic oils do, and extreme temperatures expedite this thermal breakdown. Because of the more-frequent oil changes that conventional oil requires, the difference in cost between the two is usually a wash.

Zinc in Oil

Manufacturers have been adding zinc — the common name for the zinc-dialkyl-dithiophosphate family of additives — to oil since the 1940s. Initially it was intended to be an antioxidant and prevent corrosion, but researchers soon discovered it had anti-wear properties as well. Zinc levels rose steadily in motor oils until the advent of the catalytic converter.

About Zinc

Zinc coats and reduces the efficiency of catalytic converters. Therefore, oil manufacturers reduced zinc levels to less than 800 parts per million (PPM) in most motor oils. High-performance engines benefit from higher levels of zinc, though, so zinc levels above 1000 PPM are common in racing oils.

Base Stocks

The base stock is the oil(s) that manufacturers use to produce their motor oil. Modern base stocks are highly refined, even conventional ones. The API places base stocks in one of five groups, based on how refined its constituents are.

Groups I through III are petroleum-based. The higher the number, the less harmful sulfur and the more beneficial saturates are in the base stock. Groups IV (polyalphaolefins (PAO)) and V (esters, silicones, polyglycols, etc.) are the only truly synthetic base stocks, as they are chemically engineered.

So, what makes oil synthetic? 

The answer to that question was solved legally when Mobil sued Castrol in the 1990s for using Group III base stock and calling its oil “synthetic.” Mobil maintained that synthetic oils should only be made from Group IV or Group V. Mobil lost its suit, as the ruling was that Group III oils were sufficiently altered so as to qualify as synthetic.

The result was that, in the U.S., petroleum-based oil can be marketed as synthetic if its base stock is Group III or higher.

It's proprietary!

It is difficult to determine whether a synthetic motor oil has a Group III, IV or V base stock. Manufacturers often purposely obfuscate the issue in their technical data, and the term “synthetic” has become a marketing tool rather than an honest description of a motor oil’s base stock

In truth, most synthetics are made from petroleum distillates, whether they are made with Group III or Group IV base stocks.

The main difference between Group II and Group III is that Group II has a viscosity index (resistance to change) between 80 and 119, while Group III’s is above 120. Both contain less than .03-percent sulfur.

Group IV base oils are poly-alpha olefins (PAOs), which are synthesized from natural gas condensate (U.S.) and/or naphtha (Asia and Europe), and have a naturally high viscosity index. Regardless of feed stock, Group IV oils are still derived from naturally occurring hydrocarbons.

The Best Synthetic Motorcycle Oil

#4 Lucas

Lucas Oil is one of the biggest names in racing sponsorship. The company sponsors not just race teams, but racing series for drag racing and motocross as well.

Lucas’ marketing is compelling, with claims of lower operating temperatures, extended component life and improved engine performance dominating its advertising. But, is it all true?

Lucas’ claims of being a “true racing oil” are true, at least in the sense that it has a high level of zinc additive.

Lucas HP Synthetic’s 1,058 parts per million zinc content is well above the levels considered safe for catalytic converters, but it provides extra protection for screaming motorcycle engines. 

Lucas is one of the few 20W-50 synthetic motor oils to meet the Japanese JASO-MA2 standards, which ensure that these oils are suitable for use in motorcycles in which the engine and transmission share lubricant.

Oils that do not carry this certification may contain friction modifiers that can reportedly cause clutch slipping. 

Lucas High Performance Motorcycle Oil Synthetic SAE 20W-50

Our Rating 4.5 out of 5

Lucas’ synthetic version of the other main motorcycle-oil viscosity, 10W-40, is made with both Group III and Group IV ingredients, though, and it is not a true synthetic. 

Similar to Harley Davidson oil, Lucas motorcycle oil delivers high quality performance when it is needed most. It is the result of a technology that involves blending gear and motor oils for the racing industry. This oil is easy to find at retail locations and costs much less than boutique synthetics such as Amsoil and Redline.

Users also noted that their engine temperatures remarkably decreased when using this oil. Aside from that, there is no slippage in clutch transmissions. It also has longer changing intervals. 

People also noted less engine noise as well. However, some have reported foaming issues with this motorcycle oil. They believe that it is due to the additives found in the oil.


  • Meets JASO-MA2 standards - so no shift-wrecking friction modifiers
  • Lucas has years of racing experience backing its lubricants
  • High zinc levels coat engine parts, deterring damaging metal-on-metal contact


  • Some tests suggest an unstable viscosity
  • More claims than proof to back them

#3 Royal Purple

Once a boutique oil company, Royal Purple has steadily grown in popularity since its inception in 1986. The company now enjoys a reputation for making one of the best synthetic motorcycle oils on the market.

Much like other oil companies, that reputation is built on a track record in racing that includes the sponsorship of many different types of vehicles, including motorcycles.

Royal Purple 10W-40 meets API viscosity specs and is JASO MA2 certified, so it will not cause transmission slipping in bikes with wet-sump transmissions.

Royal Purple claims its oil enables engines to run cooler, and therefore produce more horsepower than other synthetics.

The company’s own comparisons back up Royal Purple’s horsepower improvement over conventional oil, but the implication that it outperforms any of the synthetic oils on this list lacks evidence.

It admittedly contains less zinc than the others, so motorcycles with catalytic converters may benefit from Royal Purple.

Royal Purple Max Cycle 10W-40 High Performance Synthetic Motorcycle Oil

Our Rating 4.5 out of 5

The testimonials and market speak aside, Royal Purple uses Group IV base stocks and is a synthetic in the truest sense of the word. Its Synerlec additive combination improves the base stock’s shear properties and film strength, resulting in an oil that has an extended drain interval.

It also creates an ionic bond that leaves a film of oil on metallic engine parts, enabling to mate and producing smoother surfaces over time. Any anecdotal horsepower gains are a secondary benefit to a longer engine life.  


  • A true Group IV base stock in both 10W-40 and 20W-50 
  • Proven performance across racing platforms
  • Cooler running engines


  • Prices set at boutique oil levels
  • Not available everywhere oil is sold

#2 Castrol

Castrol, which has operated under the British Petroleum umbrella since 2000, now has a 4T racing oil marketed to motorcyclists.

Castrol, which has operated under the British Petroleum umbrella since 2000, now has a 4T racing oil marketed to motorcyclists.

Castrol Power 1 is a 4T synthetic oil with an additive package that Castrol calls Power Release, which it says increases power on hard acceleration.

Castrol’s comparison oil for its claim was a conventional 20W-50, though, and none of its real competition on this list was compared.

Looking over the Castrol Power 1 safety data sheet reveals both Group III and Group IV base stocks, but the petroleum distillates common in additive packages are normally distilled from petroleum.

However, up to 90 percent of the base stock is “highly refined,” which suggests a Group III base. Castrol Power 1 10W-40 has a viscosity index of 160, rivaling any oil with a Group IV base stock, but its overseas information proves it is made from Group III base stock.

Castrol is a longtime sponsor of racing motorcycles in both MotoGP and World Superbike circles. Regardless of its base stock, both 10W-40 and 20W50 Power 1 have proven track records of success on the road and at the highest echelons of motorcycle racing. 

The Trizone Technology additives reduce engine friction, but Power 1 is certified as compliant with API SL and JASO MA2 standards, meaning it won’t cause clutch slipping and is suitable of extended drain intervals.


  • Improves acceleration over conventional oils 
  • Trizone additives reduce metal-on- metal friction in high-performance engines
  • 10W-40 and 20W-50 oils suitable for use in wet- or dry-sump motorcycles
  • Costs less than other oils on this list
  • Extended drain intervals over conventional oils


  • Group III base stock
  • American advertising seems purposefully misleading

Castrol Power1 10W-40 Synthetic 4T Motorcycle Oil

Our Rating 4.6 out of 5

Castrol Power1 V-Twin 20W-50 Synthetic 4T Motorcycle Oil

Our Rating 4.6 out of 5

#1 Mobil

Mobil’s history in racing goes back to the 1970s. While Mobil doesn’t sponsor any motorcycle racing teams, it is a major player on the NASCAR and Grand Prix circuits, where engine RPM eclipse those of even the highest revving sport bikes.

In an industry clogged with pseudo synthetics, Mobil 1 motorcycle oils are refreshingly unchanging. They are based on advanced synthetic oil technology. These formulations are designed specifically for the unique needs of motorcycles.

best synthetic oil

These fully synthetic motorcycle oils are engineered to withstand the extreme heat produced by high-revving motorcycle engines and the toughest riding conditions.

The safety data sheets show PAOs and extremely low quantities of esters for both oils. These are same Group V synthetics that Mobil traditionally uses as additives to tailor its full synthetic oils to specific demands.  In this case, those demands include high flow during the sporadic cold-weather starts many motorcycles endure, as well as the high temperatures incurred during high-speed operation.

For 4-Stroke Water-Cooled Sports bikers Mobil offers Mobil 1 Racing 4T 10W-40 and for 4-Stroke Air-Cooled V-Twins Mobil offers Mobil 1 V-Twin 20W-50 such as Harley-Davidson.

For 2-Strokes, Mobil still does market Full Synthetic Mobil 1 Racing 2T but the product was discontinued in USA. It is very popular in snowmobiles and in Asia Pacific.

Mobil 1 Racing 4T and V-Twin oils are synthetic oils. Both are specifically designed for motorcycles with wet-sump transmissions, though only the 10W-40 Racing 4T carries the JASO-MA2 certification. Both oils are intended for high-performance use, with Racing 4T containing 1200 PPM of zinc and V-Twin containing 1750 PPM.

Both formulas have high shear stability, and both provide the boost in acceleration that is the hallmark of all the best synthetic motorcycle oils.

Mobil 1 Racing 4T 10W-40

Most motorcycle engine oils on the market today also require wet clutch performance.Mobil 1 Racing 4T 10W-40 fits the ticket perfectly for sports bike – on or off road.

It is designed for wet-clutch common engine/transmission systems.

It is very shear stable and thus, provide a solid, protective oil film for engine bearings, piston rings, transmission gears and other critical engine parts.

It offer high – temperature stabilities and low volatilities/low oil consumption, also offer anti-corrosion performance.

It has no friction modifiers that could lead to clutch slippage.

Our Rating 4.7 out of 5

Mobil 1 V-Twin 20W-50

Mobil 1 V-Twin 20W-50 is engineered for you “cruisers” out there with air-cooled V-Twins or even water-cooled that specify a SAE 20W-50 motor oil.

What makes it one of the best motorcycle oils available is that it was scientifically engineered to withstand the extreme heat that air-cooled motorcycle engines produce using Synthetic Base Oil technology along with synergistic Additive technology.

It also allows riders to go longer and farther between oil changes.

The bike warms up faster and has less engine noise.

Users also reported that their engines have remarkably improved performance as well.

Our Rating 4.8 out of 5


  • Enjoys a reputation as one of the few Group IV, motorcycle-specific oils offered by a major oil company
  • Mobil has a proven track record of success and support for truth in synthetic advertising
  • Neither formulation contains shift-wrecking friction modifiers
  • Readily available at most auto parts stores


  • Likely due to its confusing advertising of its other synthetics, Mobil makes it difficult to verify its use of Group IV base stocks in its motorcycle oils
  • High Price Tag


American riders looking to ensure that the oil they put in their motorcycles is a true, Group IV synthetic are in for a wild ride through mixed messages and convoluted advertising. That’s what happens when technical language becomes marketing speak. 

In the U.S., synthetic only means highly refined, as Group III mineral oils can be nearly as wax-free as Group IV PAOs, with nearly equivalent flash points and high-temp pour points. In extremely cold environments, Group IV is still king, but we don’t normally ride at below-freezing temperatures to notice a difference.

In extremely hot environments, though, synthetics retain their viscosities better, and hence better protect engine components. This is where synthetic oils earn their keep in a motorcycle. 

Most bikes operate at revs that would be past redline on the average sports car. For the money, Mobil 1’s Racing 4T and V-twin synthetics provide all the protection high-revving and hot-running engines need. They are readily available at most auto stores, and they win tend to cost less than the boutique oils, making them likely the best synthetic motorcycle oil options. 

What oil are you using? Would you consider changing your oil? Let us know. Any questions or comments please post them in the comment section below. Happy riding!

Related Posts:

1. What is the Best Synthetic Oil?

2. The 4 Best Automatic Transmission Fluids Available

3. The 6 Best Gear Lubricants for your Vehicle

4. The Best Synthetic Grease for Complete Automotive Care

5. The 5 Best Oil Filters Review

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