How to Adjust Valves on a Moped

You can replace your moped's valve to adjust acceleration, top speed and performance.

Older moped models came stock with a carburetor, which controlled how much fuel the single-piston engine received. This carburetor was open to modification for enhanced performance, which many owners chose to do themselves. With some tweaking, you can replace the carburetor valves to improve the speed, acceleration and performance of your moped.

Things You'll Need

• Wrench
• Screwdriver
• Replacement jet set

Instructions

1. Remove the carburetor on your moped by unscrewing the hose clamp that connects it to the engine using a wrench. The carburetor sits directly above the engine block.

2. Strip the carburetor down to its bare bones. Unscrew the throttle screw, located at the top of the carburetor, using a screwdriver. Pull out the throttle mechanism, located inside the carburetor.

3. Locate the small golden screw inside the carburetor. This screw, called the jet, serves as the moped's "valve." Unscrew this screw, and compare it with your replacement jet set.

4. Place a larger jet into the carburetor to increase fuel flow into the engine, resulting in better moped performance.

5. Replace the throttle mechanism, and connect the carburetor back onto the engine. Give your moped a spin to see how the new jet works.

Tips & Warnings

• You can also upgrade your moped's actual carburetor to give it a big boost in performance.

References

• Scooter Therapy: How to Repair the Carburetor on a Moped