All KYMCO 50cc and 90cc model ATVs are restricted in order to meet the ANSI (American National Safety Institute) standards, which limit a 50cc youth ATV to 10 MPH and a 90cc youth ATV to 15 MPH. This standard also states that the speed limitations can be removed according to the skill of the rider. The following three-step system will allow the rider to progress in stages. Please see the instructions below for the removal of these steps.

KYMCO has chosen three methods for reducing the speed of the Youth ATV’s. They were designed for safety and durability of the engine.

  • An RPM limiter in the CDI box

  • Belt travel limitation in CVT

  • Throttle limiter

These can be de-restricted individually to increase speed to meet the driver’s skill level. BUT, keep in mind that these restrictions are designed to keep the young rider as safe as possible. It is our first priority to ensure that our young riders do not ride above their skill level. USE GOOD JUDGEMENT!

The de-restricting steps are as follows:


The CDI box has a rev limiter designed to cut the spark once the engine exceeds a pre-determined RPM level. This should be the first step in the de-restriction process.

50cc Models:

1. Locate the CDI box under the seat.

2. Locate the green wire loop on the end of the box.

3. Cut the green wire loop with wire cutters. Always leave enough room to re-attach the wires if needed. (See Photo #1)

90cc Models

1. Locate the CDI under the seat.

2. Locate the set of wires connected to the CDI.

3. Locate the light green wire incorporated into the 4-wire connector and cut it with wire cutters. CAUTION: There are two light green wires in the CDI box. Be sure to cut only the one that is connected to the 4-wire connector.  (See Photo)


The second restriction is located in the rear clutch on the CVT system. This limits the travel of the pulley and will only allow the belt to travel a limited distance. This procedure is the same on both the 50cc and 90cc models.

1. Remove the CVT cover located on the left side of the ATV. Note: The footboard must be removed on the 90cc only.

2. Remove the nut on the front and rear pulley.

3. Remove the front outer pulley and the entire rear pulley including the belt.

4. Remove the clutch drum from the rear pulley.

5. Disassemble the rear pulley and remove the spacer as shown in Photos 3 & 4 below.

6. Reassemble the clutch and re-install on the ATV in reverse order as above instructions.


The throttle limiter should be adjusted as the final restriction and only in accordance with the user’s skill level.

1. Locate the throttle limiter. (See Photo)

2. Hold the screw in place with a Phillips head screwdriver and loosen the lock nut using a 8mm wrench.

3. Rotate the screw adjusting it outwards to increase speed.

4. Lock screw in place once the desired speed is attained, by holding the screw in place and tightening the 8mm nut.