Some performance-enhancing substances are completely legal.

Bel-Ray doesn’t just lubricate your bike’s moving parts, it brings your engine to life. Pistons pump more efficiently, gears interact with greater purpose, bike chains perform the way they’re supposed to - everything becomes more agile, all elements move in harmony.

Bel-Ray unleashes your bike’s full potential, while increasing the life-span of each moving part. There’s less friction, so there’s less abrasive wear and your engine runs cleaner too. When it matters what goes into your bike, use Bel-Ray total performance lubricants. Flex Your Engine.


Popular products

Understanding Oil Viscosity

Oil viscosity refers to how easily oil flows at a specified temperature. Thinner oils flow more easily at low temperatures than heavier, thicker oils that have a more honey-like consistency. Thin is better for easier cold weather starting and reducing friction, while thick is better for maintaining film strength and oil pressure at high temperatures and loads.

Oil viscosity is measured and given a number, which some people also refer to as the “weight” (thickness) of the oil. The lower the viscosity rating or weight, the thinner the oil. The higher the viscosity rating, the thicker the oil.

Motor Oil Viscosity Ratings

Viscosity ratings for commonly used motor oils typically range from O up to 50.

  • With multi-viscosity oils, a “W” after the number stands for “Winter” grade oil
  • The numeric value of the first number (example 5W-20) is a reference point to the lowest applicable temperature
  • The SAE grade is a reference point to the oil viscosity at operating temperatures

Engine Oil Ratings Reference Guide


(American Petroleum Institute)

Test engine oil for performance, protection and cleanliness

Does not relate to clutch or transmission performance


“S” for Service

(Gasoline Engine Applications)

“C” for Commercial

(Diesel Engine Applications)


The Rating
  • Further down the alphabet = higher ratings
  • J is currently most manufacturer’s minimum
  • Ratings test for: wear resistance, oxidation, corrosion resistance, deposit control and more
  • Oil must pass all tests to obtain rating


(Japanese Automotive Standards Organization)

MA: Minimum required for engines that share its oil with transmission and clutch

  • Allows enough friction between your clutch plates for proper operation

MA2: Highest rating (higher amount of friction within the clutch)

  • Consistent clutch feel even at high operating temperatures
  • MA2 advantages: less wear over time and low clutch slip giving your motor more horsepower and torque

MB: Not suitable for transmission and wet clutch

  • JASO MB rating for non-wet clutch motorcycle engines

Most of the Bel-Ray 4-Stroke Powersports line meets or exceeds the API SN standards and are JASO MA2 registered.
The few products that don’t meet those standards were formulated to meet specific criteria within the applications for which those products were created. (Example: Bel-Ray Friction Modified Thumper Oil API SN JASO MB was designed for dirt bike engines that used separate oils for the engine and transmission.)