When I have my motorbike getting fixed at the shop, I use my old 50CC scooter to get around. However, being a speed fanatic, this 50CC  scooter runs too slow for me, even for local errands. So my weekend project will be derestricting my 50CC scooter to be at least half as fast as my motorbike. To do this, you need to understand the restrictions on a 50CC scooter, how to remove them correctly, and the legalities of derestricting your scooter.

To derestrict your 50CC scooter, you should remove your scooter’s kickstart, loosen the pulley wheel and remove the rev limiter(washer) from the pulley rod. Other ways you can derestrict your scooter, depending on the make and model, is to remove the CDI, remove the oversized variator boss or replace the jet on the variator system with a larger main jet. Read more on how to safely derestrict your 50 CC scooter and also avoid legal penalties.

 What is a restriction?

Manufacturers restrict 50CC scooters to the speed limit of 30mph in compliance with your state’s scooter laws. 50CC engines on scooters perform very well in terms of speed, but to stay within the state limits, manufacturers have to either add or replace parts to keep the speed within legal limits. Most manufacturers install a restrictive washer in the pulley rod which prevents high speed. Other scooter manufacturers add other restrictions, which include:

  • An oversized boss in the variator system by preventing the full range of gear ratios
  • A smaller carburetor jet that limits fuel flow
  • An electronically limited CDI or ignition module stops the engine from firing any higher by preventing the ignition from firing any further and restricting the engine to about 700rpm.

Derestricting a scooter is removing or replacing these restrictions by increasing the engine’s performance to achieve its full potential and considerably higher speed of around 75kph. The easiest derestriction is removing the restrictive parts such as the restrictive washer, exhaust dummy pipes, and carburetor opening restrictions. The other way is replacing restrictive parts with unrestricted replacement parts such as the electronically limited CDIs, diameter restricted inlet manifolds, and increased length exhaust manifolds.

How fast can a stock 50CC scooter go?

Typically, a 50CC scooter that comes with a restricted engine has a speed limit of 30 mph(48kph), which is excellent for local and short-distance trips around town. With a derestricted engine, a 50CC scooter can go at speeds of around 40-60mph (65-96kph), suitable for open roads and longer journeys.

How do you derestrict a 50CC scooter?

You can easily derestrict your 50cc scooter by yourself using three wrenches and a basic understanding of the scooter’s variator system, with the method explained below.

Things You’ll Need

  • Impact wrench
  • Strap wrench
  • Socket wrench.


  • Locate the kickstand from the side of your scooter. Remove the kickstand pin attaching the kickstand to the scooter’s side by slightly loosening the bolt and pulling out the kickstand pin.
  • Find the variator system, also known as the carburetor, located underneath a plastic intake cover. Remove the bolts holding the intake cover in place to expose the variator system. The variator system looks like a long, thin tubular device.
  • Remove the kickstart metal lid using a socket wrench to unscrew the three bolts at the bottom and three at the top. Remove the bolts in the order as you would the tire rim bolts; top right, bottom, left, top middle, bottom middle, top left, and bottom right.
  • Use a strap wrench to secure the front wheel pulley from rotating. Wrap the strap around the pulley wheel, tighten it on the wrench, and position the wrench’s handle underneath the rear pulley system. The wrench will jam the wheel and allow you to unscrew the bolt securing the wheel.
  • Disengage the front pulley wheel from the pulley system by using the socket wrench to remove the single bolt holding the front wheel pulley in place. The pulley wheel limits how fast the scooter can go when you fire up the engine. Loosening the pulley wheel allows the pulley belt to move freely.
  • Remove the washer from the front pulley rod. The washer is the device that restricts your 50CC scooter’s speed by adding space between the pulley belt and the pulley rod, therefore, preventing the belt from pulling the rod to its maximum and accelerating the scooter.
  • Reassemble the variator system by putting the front pulley wheel back onto the pulley rod, replace the variator case cover and the intake case, and put back the kickstand on the scooter.

Keep in mind that removing the washer does not increase your engine’s capacity(CC); it allows the 50CC engine to perform at its maximum capabilities. After derestricting the engine in some scooters, you may have to replace the carburetor’s main jet to increase fuel supply to match the engine’s increased revenues and fresh air supply.

Check this too: How Fast Does a 150CC Scooter Go?

Is it legal to derestrict a 50CC scooter?

Technically, it is not illegal to derestrict a 50CC scooter. However, it is unlawful to use a scooter that can run over 30 mph without the proper driver’s license and if the rider is under the age of 17 years. In the U.S., you should have the appropriate license M-class license. When you derestrict a 50CC scooter, it can travel up to 60mph, so you should re-register your scooter as a motorcycle and get the license. Otherwise, you may be liable for hefty penalties or have your license revoked if you get caught. In the U.S., you should only drive a derestricted scooter:

  • If you’re 17 or over
  • You own a provisional driving license or a full driving license.
  • If you have completed the CBT test

In some countries like in the European Union, it is illegal to derestrict 50CC scooters with a provisional license. In contrast, in other countries like Italy, Japan, Netherlands, it is entirely illegal to modify a 50CC scooter with whatever license.

It is essential to keep in mind that many insurance companies will nullify your cover when you derestrict your scooter. So, if you cause an accident or end up in one, you will be liable for your own medical, legal, and compensatory costs, regardless of your riding speed.


If you follow our easy guide, you will be able to easily derestrict your 50CC scooter to go at higher speeds without compromising the quality of your scooter. To avoid any legal penalties, you have to re-register your derestricted scooter as a motorcycle since its speed passes the 30mph speed limit legislated by law