The Essential Guide to Tuning Your 50cc Moped

Looking to get the best experience from your 50cc moped? Learn how to tune and tweak your machine. You’ll discover new levels of performance and enjoyment every time you ride.

With a few mechanic’s tools and a basic understanding of combustion engines, you can get the power you want from your two-stroke or four-stroke moped.

Here’s what you need to know about the art and science of tuning your scooter:

Keys to Power of Your 50cc Moped

Three components that affect power and performance are: air intake, carburetor, and transmission.

In combustion engines, air plus fuel equals energy to move the parts within the transmission, which drives the motion of the moped.

Adjusting any of these components can affect the performance of the others. Finding the right balance is the art of tuning a 50cc moped and keeping it road legal.

Here’s a pretty cool video series that talks about how to make your scooter faster. There’s a few different videos but here is the first one to get you started.

Air Filter

The first step to tuning your moped is checking the air filter. Keeping it clean or swapping a low-flow for high-flow filter will increase the amount of air that enters the carburetor. That changes the air to fuel ratio.

Increasing the amount of oxygen in relation to gasoline offers several benefits:

  • Faster and smoother ignition
  • Improved fuel efficiency
  • Reduced emissions
  • Less residue within the carburetor


To gain the full benefit of increased airflow, make sure your carburetor is clean. You can also boost the performance of your 50cc moped by over-boring your carburetor to increase capacity.

That requires some time and a certain amount of mechanical know-how. Instead, more people opt for replacing a standard carburetor with a larger one.

Spark Plugs

Dirty or worn out spark plugs can make starting and running your moped sluggish and frustrating.

When tuning your moped, remove the spark plugs. Clean them with a small wire brush or spray-on plug cleaner. Also, make sure they are properly gapped by using a gapping tool.

If that doesn’t give you the improved performance you want, replace them with new plugs.


There are a couple of ways to tune-up your moped’s transmission for better performance.

Changing the size of the front and/or rear sprockets affects performance. The same is true for modifying the gear ratio.

Gear size is measured by the number of teeth. Gear ratio is the number of teeth on the front sprocket compared to that of the rear sprocket. The gear ratio reflects the rate of rotation transfer from the engine to the rear wheel.

With a high gear ratio, the rear wheel rotates more for every turn of the front sprocket. This makes it more difficult to accelerate, especially from a full stop. But it does improve speed at high RPMs.

With a low gear ratio, the rear wheel rotates less for every turn of the front sprocket. This can improve the acceleration of your moped.

You can also change the cylinder heads to alter compression. Compression is the ratio of the cylinder’s volume compared to the volume contained between the piston crown and cylinder head.

More compression gives you greater low-end acceleration. But too much can cause “knocking” and eventually damage the cylinders.

Experiment and Discover

Tuning your bike so that it gives you the power and performance you want can take a few attempts. Until you find the best mix for you, experiment. Change one factor. Give yourself time to experience the effect on performance before tweaking something else.

But be warned. Tuning your 50cc moped in search of optimal performance can become habit-forming!