20W-50 Motorcycle Oil, Primary and Transmission Fluids:

Some V-twin motorcycles like the modern Indian and Victory bikes, use a shared sump meaning, they use the same lubricant in the engine, transmission and primary chaincase. Most Harley-Davidson motorcycles use a separate sump for reach lubricant. This presents Harley owners with a choice: use the same lubricant in all three areas of the bike or use a separate lubricant formulated and labeled for each area. The 20W-50 for the engine; The V-Twin transmission for the transmission, or the V-Twin primary for the chaincase. This article offers guidance for deciding what’s right for your customers.

Amsoil recommends 20W-50 synthetic V-twin motorcycle oil in the engine, transmission and primary chaincase on most Harleys.

Amsoil 20W-50 offers:

  • Convenience – Riders buy and install one lubricant. This reduces costs and results if you half- used bottles of oil lying around in the garage.
  • Simplicity – Remembering to buy one lubricant is far easier than remember three.
  • Great all round performance in all three areas of the bike.

Amsoil formulated 20W-50 synthetic V-twin motorcycle oil to be an excellent all round lubricant. It delivers outstanding engine protection due to a proven ability to fight wear, reduce heat, maintain cleanliness and prevent corrosion during storage.

Synthetic V-twin motorcycle oil also boasts the shear- stable formulation. It resists viscosity lost despite the intense pressure and churning action of high rpm transmission gears, allowing it to deliver reliable transmission protection. Synthetic V-Twin Motorcycle Oil meets JASO MA/MA2 standards and is wet-clutch compatible for excellent performance in the primary chaincase. Its frictional properties are dialed in to allow the clutch plates to engage and disengage without loading or slipping for smooth shifts.

Despite these benefits, some riders question of practice of using one lubricant in all three areas of their bikes. They have a difficult time accepting that motor oil can also protect the transmission and primary case.

What are the differences?

Synthetic V-Twin Transmission and Primary Fluids

Synthetic V-twin transmission fluid and synthetic V-twin primary fluid are formulated to protect just one area of your bike rather than all three. This fact allows Amsoil to engineer each lubricant for its precise application.

Synthetic V-Twin Transmission Fluid:

Synthetic V-twin transmission fluid has a high viscosity than 20W-50 synthetic V-twin or motorcycle oil. A higher viscosity, or “thicker”, lubricants can help quiet noisy transmission gears and enable smooth shifts. The lubricant develops a slightly thicker fluid film on gears which provides a cushion to help diminish lower “thunks” and gear noise.

Synthetic V-Twin Primary Fluid

Amsoil synthetic V-twin primary fluid is designed only to protect primary chaincase components. Its viscosity is similar to SAE 50 motor oil. Formulating it as a straight weight lubricant which naturally offers an advantage in shear stability over the other multi-viscosity lubricants. Amsoil 20W-50 synthetic V-twin motorcycle oil is absolutely shear stable and will not thin out from mechanical activity. This helps the fluid remain thicker, which helps it cling to the compensator without being a “flung” off as easily for maximum protection. In Harleys, the compensator acts as a shock absorber to prevent engine vibration from affecting the transmission. Compensator wear often leads to knocking or ticking noise. Synthetic V-twin primary fluid also clings well to the chain for excellent wear protection, and it’s wet clutch compatible formulation meets JASO MA/MA2 to requirements

One oil or three?

So which is the better route for Harley owners, it depends on what the customer values.