AMSOIL Synthetic oil in Harley Davidson

Synthetics and Harley Davidson bikes is a topic of much discussion. Harley, like most auto manufacturing companies, refused to accept synthetics for years. It was only recently that HD, the last remaining American manufacturer to still ostracize synthetic oil, finally came out with their own synthetic. So, the company that refused to accept synthetics for 100 years finally has their own; SYN3.

Buy your bike from a good, quality bike manufacturer. Buy your oil from a good, quality, synthetic oil manufacturer. If you want to know the facts regarding motorcycle oil, please take a few minutes to view the online presentation "A Study Of Motorcycle Oil". This motorcycle oil presentation is exhaustive, and provides good third party information. The new Harley Davidson Syn3 has now been tested as well. It didn't do so well.

Amsoil 20W-50 Motorcycle oil vs. Screamin' Eagle Syn3

Harley Davidson warranty and Amsoil

I'm sure you've heard the debate about synthetic oil impacting your warranty. It's illegal for a manufacturer to void a warranty based on the brand of oil used. It's called the Magnusson Moss Act. You can read it here, as well as the Amsoil warranty on oil and filters. Basically, manufacturers cannot specify a BRAND of oil, as long as the oil meets specifications.

You still read a lot of misinformation, but now you have access to the facts. For example, in 2007 the Harley Davidson Enthusiast magazine, which I subscribe to, had this question from a reader. “Would I void the warranty if this lubricant is not specified in the H-D owner’s manual?”

The editor's answer; “SYN3 is the only synthetic motor oil that does not impact your 24-month, unlimited-mile factory warranty.” Of course, this is NOT TRUE. The next issue of the magazine, they had received dozens of replies objecting, and even a reply from Dean Alexander, VP  at Amsoil. The Enthusiast clarified the issue in an interview with the Lubricants Category Manager at Harley, Mr. Larry Gutjahr.  “No, that’s not true. We cannot and would not void a warranty for use of another brand of oil." Larry Gutjahr, P&A Lubricants Category Manager, Harley-Davidson.

There have been millions of miles put on Harley Davidson motorcycles using Amsoil. Any remaining concerns should be resolved by reviewing the test information mentioned here, as well as the warranty information. Amsoil is also now the official Harley oil of Sturgis, and Daytona Bike week, so the tide is turning. Amsoil is also the oil sponsor of the AMA Pro Daytona Sportbike race at Daytona, for those who don't hate sportbikes.

Amsoil official oil of SturgisAmsoil official oil of AMA Sportbike DaytonaAmsoil official oil of Daytona Bike Week

Harley Davidson oil product selection

To access the online product selector please check the Amsoil product selector. This will help determine the correct air filter, oil filter and synthetic oil for most motorcycles including; Harley, Buell, all the Asian bikes, Aprila, KTM, Ducati, Cagiva, Indian, Moto Guzzi, BMW, BSA as well as snowmobiles, ATVs and watercraft.

AMSOIL has synthetic oil products that riders have been using in v-twins for years. Amsoil also manufacturers chrome oil filters for your Harley needs. There are two basic approaches to running AMSOIL synthetic in a big twin. One oil meets the specs for all three uses;

SAE 20W-50 Synthetic Motorcycle Oil (MCV)
High Performance Lubricant for Engines, Transmissions and Primary Chaincases

Some riders prefer to match the oil weights to the different needs. These riders usually go with something like this; 20W-50 oil in the crankcase, AMSOIL synthetic 10W-40 oil in the primary chaincase, and AMSOIL Severe Gear 75W-90 Synthetic Gear Lube in the transmission.

Personally, I run the 20w-50 in all three cases, and it's been working great. This year I rode through Dragon's Tail, all over Arkansas, and local riding as well.

Amsoil Synthetic Oil also offers a synthetic 2-stroke oil, as well as a full line of Harley Davison oil filters in both black and chrome.

AMSOIL Synthetic 20W-50 Motorcycle Oil (MCV) is a premium oil designed for those who demand the absolute best lubrication for their motorcycles. AMSOIL MCV is the result of extensive research, and it is specially formulated to excel in all areas unique to motorcycles, including high temperatures of air-cooled engines such as Harley Davidson® V-Twin, wet clutch lubrication, extreme pressure regions of gears and chains and rust common to short trips and storage.

Reduces Friction, Heat and Wear
In high heat conditions, engine protection is not sacrificed with AMSOIL Synthetic Motorcycle Oil. It has exceptional
high-temperature film strength and contains a heavy treatment of anti-wear additives to reduce wear regardless of the
operating conditions. AMSOIL 20W-50 Motorcycle Oil is thermally (heat) stable and contains maximum levels of oxidation inhibitor additives. It is extremely resistant to breakdown and engineered to prevent damaging sludge and
carbon de-posits for superior engine cleanliness.

Provides Extreme Pressure Quality Protection for Gears and Chains
With AMSOIL MCV, there is no need for separate transmission or primary chaincase lubricants. It is absolutely shear stable and will not thin out from mechanical activity. AMSOIL MCV performs like a gear lube without the negative effects of extreme pressure additives. In the FZG gear test, AMSOIL MCV achieved a perfect score with a “zero” wear rating (see photo below).

FZG Gear Test (ASTM D-5182)
Pass Example: AMSOIL MCV
Passed Stage 13, Total Wear 0 mm
Failure Example: Lucas High Performance
Passed Stage 11, Failed Stage 12,
Total Wear in Stage 12, 160 mm
Amsoil MCV superior rust protection
Lucas High Performance failure

Delivers Superior Rust Protection
Motorcycles are prone to rust from storage, humidity and short drives. Rust can cause major damage such as roller bearing failure, uncontrolled wear, compression loss and blow-by. Good rust protection, however, comes by design and is not natural to engine oils. Unlike many motorcycle oils, AMSOIL MCV contains special anti-rust agents. It passes the ASTM D-1748 humidity cabinet rust test and clearly demonstrates superior rust protection (see photos below).

Rust Test ASTM D-1748
Pass Example:
Fail Example
Castrol V-Twin
Amsoil MCV passed rust test
Castrol V-Twin failed rust test
Amsoil MCV passed rust test
Castrol V-Twin failed rust test

Provides Excellent Wet Clutch Performance
AMSOIL MCV contains no friction modifiers and promotes smooth shifting and positive clutch engagement. AMSOIL MCV controls heat and prevents slippage and glazing, and its high TBN resists acids that can degrade clutch material, helping improve clutch life.

Amsoil MCV Shear Stability

AMSOIL Synthetic 20W-50 Motorcycle Oil is recommended for air or liquid cooled 4-stroke engines. It meets SAE 90, API GL-1 gear oil requirements and is recommended for transmissions and primary chaincases. AMSOIL MCV is recommended for Harley Davidson®, Buell®, KTM, Ducati®, Aprilia®, BMW®, Triumph® and other motorcycles where 15W-50 or 20W-50 engine oils or SAE 90, GL-1 gear oils are used. Not recommended where an API GL-4 or GL-5 gear oil is required.

AMSOIL Synthetic 20W-50 Motorcycle Oil is compatible with conventional and synthetic motor oils; however, mixing oils may shorten the oil life expectancy and reduce the performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed.

Aftermarket oil additives are not recommended for use with AMSOIL motorcycle oil.

Recommended for use up to twice the motorcycle manufacturer change interval (miles/hours) or one year, whichever comes first, in engines, transmissions and primary chaincases. For Big Twin Harley-Davidson transmissions only, follow the Harley-Davidson recommended drain interval for synthetic oil of up to 20,000 miles or one year, whichever comes first. When using an engine filter other than AMSOIL Ea, change the filter at standard intervals.

For off-road use, change AMSOIL MCV at motorcycle manufacturer intervals.

Racing or modified engines are excluded from extended drain interval recommendations. Oil changes are at the owner’s discretion.


SAE 20W-50 Synthetic Motorcycle Oil (MCV)

Kinematic Viscosity @ 100°C, cSt (ASTM D-445)


Kinematic Viscosity @ 40°C, cSt (ASTM D-445)


Viscosity Index (ASTM D-2270)


Pour Point °C (°F) (ASTM D-97)

-39 (-38)
Flash Point °C (°F) (ASTM D-92) 240 (464)
High Temperature/High Shear Viscosity @ 150°C , 1.0 x 106 s-1 (ASTM D 4683), cP 6.02
Four Ball Wear Test (ASTM D-4172 @ 40 kgf, 150°C, 1800 rpm, 1 hour), Scar in mm 0.37
FZG (ASTM D-5182), Load Stage Pass (Wear in mm) 13 (0mm)

Noack Volatility, % weight loss (g/100g) (ASTM D-5800)

Foam (ASTM D-892, Sequence I, II & III) 0/0/0
Shear Stability Kurt Orbahn (ASTM D-6278), % viscosity change 120 cycles 0.25
Rust Test - Humidity Cabinet (ASTM D-1748) No Rust, Pass

Total Base Number


Here are my bikes;

Amsoil Harley Davidson oil runs this Dyna

Dyna, at Deal's Gap. Limited edition "Blade" radical paint; 1 of only 200 made. this is a 100 year anniversary HD. Of course, it's running AMSOIL.

Amsoil Harley Davidson oil runs this Dyna

2008 Nightster with Vance and Hines "short shots" and forward controls. With the 2003 "100 anniversary" Dyna, somewhere in Arkansas. Nightster has fuel injection and the chip has been flashed to support the Short Shots. Here is a close up of the Short Shots on a Sportster, from the V&H site (below).

Short Shots from Vance and Hines - detail with forward controls. Amsoil runs this bike.

V&H Short Shots on a Nightster.

Amsoil runs this Keith Black gutted big bore kit 83 hp Sportster.

88 Dyno certified HP. Looks good, runs like a bat, not too comfortable. I paid attention to the all Harley drags in KC, and I think this bike could have took the Sportster division. There was one other contender in KC while we owned this bike. Sold it to someone in Springfield, MO. The 2 into 1 Vance and Hines pipe sounded CRAZY. We rode with about 15 bikes, from Ducati's  and BMW's to Indians and HD's and when we pulled in for gas, everyone came over to look at this bike 'cause of the nasty sounds it was singin'. This bike was built and owned by Cody at St. Joseph Harley Davidson. St. Joe HD is my favorite, great dealer and great service operation. Not like some others I won't name in KC. .... but if you want to know, email me.

Big bore kit, Keith Black high top pistons and rods, all the cheesecake. Carb, not injected.