What’s The Best Oil for My Scooter? 

Scooter oil should resist heat and viscosity loss while meeting JASO MA/MA2 requirements.

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AMSOIL Formula 4-Stroke® Synthetic Scooter Oil
by John Baker
May 23, 2022

People seem to snap up scooters every time gas prices hit new highs. With dire predictions for higher prices this summer, it’s a good time to be in the scooter sales business. Once you get your gas-saving two-wheeled wonder, you’ll need oil for your scooter, and you’ll probably have questions: What’s the best oil for a 50cc 4-stroke scooter? What do I need to know about 2 stroke scooter oil? We’ll tackle those questions here.

Oil For Your Scooter: A Primer

It’s tempting to assume that small = simple when it comes to your scooter engine, be it a 4 stroke or 2 stroke. However, that’s not the case. Scooters face tougher operating conditions and, consequently, are harder on oil than most people assume.

High-Revving, Hot Engines

Although some top-end scooters are liquid cooled, like the Honda* Metropolitan,* most are air cooled. Air is inherently less efficient at removing heat from the engine than coolant/water mixtures.

For example, sitting in traffic on a hot summer day as the sun radiates off the asphalt and heats the engine is a recipe for overheating since the scooter isn’t moving to generate cooling air over the engine.  

Plus, scooter engines can rev high, especially if you get a little rambunctious on the throttle. These conditions create heat and stress, which oxidize the motor oil and cause it to chemically break down. Oil that has oxidized causes a few problems:

  • Reduced wear protection
  • Increased oil viscosity, which reduces energy efficiency
  • Shortened oil life

Gears Can Tear Apart Oil for Scooters

Many scooters today use continuously variable transmissions (CVT). They offer the benefit of infinite gear ratios, meaning the engine is always in its fuel-efficiency “sweet spot.” Plus, you don’t have to bother with shifting.  

For scooters with stepped transmissions, the engine oil is often used to lubricate the transmission and gearbox, too. Churning, meshing gear teeth create shearing forces that can tear apart oil molecules, a process known as mechanical shear.

Oil that has sheared permanently loses viscosity, which interferes with the oil’s ability to develop a strong protective film on engine components, gears and bearings, reducing wear protection.

This means that when you’re looking for oil for your scooter, be it a 50cc, 150cc or 250cc model, an oil that resists viscosity loss due to shear in addition to the negative effects of high heat should be your choice.

Shift To Better Clutch Protection

If that isn’t enough, the oil must lubricate the clutch on scooters equipped with a wet clutch. “Wet” simply means the clutch is immersed in oil, as opposed to a dry clutch.  

Oils with the incorrect frictional properties can cause the clutch to slip or feel “loose” or “sloppy.” In this case, look for an oil for your scooter formulated to be wet-clutch compatible. Check the label to ensure it’s recommended for JASO MA/MA2 requirements, which signifies its suitability in scooters that use a wet clutch.

What’s The Best Oil For 50cc, 150cc & 250cc 4 Stroke Scooters?

So, to recap, look for a scooter oil that does the following:  

  • Resists elevated heat
  • Maintains viscosity despite the shearing forces of meshing gears
  • Meets JASO MA/MA2 requirements for wet-clutch compatibility

Which is the best oil available? We think it’s AMSOIL Formula 4-Stroke® Synthetic Scooter Oil. No surprise since you’re reading the AMSOIL blog right now.

Now it’s up to us to prove it.  

For starters, AMSOIL Synthetic Scooter Oil is formulated using high-quality synthetic base oils. They form a stronger, more resilient fluid film on parts than conventional base oils for maximum wear protection. They also naturally resist heat better, which helps resist harmful engine deposits that reduce engine power over time, while also promoting longer oil life due to decreased oxidation.  

For you tech nerds, check out the oil’s performance in the Noack Volatility Test (ASTM D5800).  

  • 5.4% weight loss (g/100g)

This means the oil only lost 5.4% of its weight after being heated to 150°C (302°F) for a period of time, far hotter than your oil should ever get.

When subjected to extreme heat, the lighter molecules in conventional oil can evaporate and leave behind heavier molecules. This is often what’s happening when an engine is said to be “burning” or “using” oil. AMSOIL Synthetic Scooter Oil withstands extreme heat to deliver excellent protection.

In addition, it meets JASO MA/MA2 requirements and provides excellent clutch protection and shift quality.

What About 2 Stroke Scooter Oil?

Two-stroke scooters also create stressful conditions that can lead to engine wear if the oil isn’t up to the challenge.  

The oil must withstand elevated heat and engine rpm, which can overwhelm some 2 stroke oils and lead to piston scuffing and engine damage. The oil must also burn cleanly, otherwise it can form heavy carbon deposits on the piston crown, rings and inside the exhaust port.  

Heavy crown deposits can lead to pre-ignition, which is an abnormal combustion event that disrupts engine timing and, in extreme conditions, wrecks the piston or rod bearings. Either way, it’s not a cheap fix.

Piston-ring deposits, meanwhile, can cause the rings to stick, which reduces compression. Lost engine compression equals lost engine power.  

Finally, 2 stroke scooter oil that doesn’t burn cleanly can cause deposits to form in the exhaust port. If bad enough, they restrict airflow, which leads to hard starting and power loss.

What’s The Best 2 Stroke Scooter Oil?

No surprise – we think it’s AMSOIL DOMINATOR® Synthetic 2-Stroke Racing Oil. This oil is formulated with higher-viscosity synthetic base oils to withstand high heat and pressure. Its anti-friction chemistry adds an extra measure of protection against piston scuffing and bearing wear, helping protect your high-revving 2 stroke scooter engine. 

It’s also formulated with clean-burning synthetic base oils and powerful high-temperature detergent additives for exceptional deposit control. This helps prevent power-robbing carbon that causes ring sticking, exhaust-port blocking and pre-ignition.  

Sure, it’s not a scooter engine, but check out how DOMINATOR Synthetic 2-Stroke Racing Oil protected this professional snowmobile racing engine that lost all its coolant after a hose clamp broke.

Get The Best Oil For Your Scooter

Hopefully, this information has convinced you to use the best oil you can find for your scooter’s engine, transmission and gearbox. That relatively small, simple engine used to power your scooter is much tougher on oil than it first appears. 

Whether you ride a 4 stroke or 2 stroke scooter, and whether its engine weighs in at 50cc, 150cc, 250cc or something else, AMSOIL formulates an oil for your scooter that’ll deliver excellent protection against wear and deposits.

That’ll keep your scooter running at peak performance no matter how high gas prices climb.

by John Baker

AMSOIL Technical Writer and avid avid DIYer with 12 years in the synthetic lubricants industry, who enjoys making technical topics in the automotive, powersports and industrial markets easy to understand.

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AMSOIL Formula 4-Stroke® Synthetic Scooter Oil