How to Derestrict a Scooter

Modern scooters use a belt drive for a transmission whereas vintage scooters used gears.

Derestricting a scooter involves removing certain parts to allow the scooter to perform at its full capacity. Manufacturers design scooters with performance modifications so they comply with laws where they are sold. However, these modifications are add-ons that can be removed with a bit of work and mechanical know-how. To derestrict a scooter, you can make adjustments to the air intake system and transmission.

Things You'll Need

• Screwdrivers
• Foam air filter
• Banjo clamp
• Socket wrench and sockets
• Rubber mallet
• Allen wrench set
• Metal pan
• Impact wrench
• Scooter owner manual
• New transmission case gasket

Instructions

Air Intake Modification

1. Open up the air filter container of the scooter (usually located near the rear wheel) with a screwdriver. Remove the air filter included and block off the existing air inlet if necessary.

2. Locate the carburetor and disconnect the remaining part of the air inlet hose with a screwdriver. Attach a new separate foam air filter onto the carburetor air intake and secure with a banjo clamp and screwdriver.

3. Discard the old air filter and inlet hose materials. Start up the scooter and let it run for a bit. Throttle the scooter and measure the performance to confirm it now throttles higher than it did with the old restricted intake. Results should show a faster throttle response without the restrictive intake.

Transmission Derestriction

1. Remove the bolts securing the transmission cover onto the left side of the engine assembly with a socket wrench or Allen wrench. Tap the cover loose (if stuck) with a rubber mallet after releasing the bolts. Place the loose parts in a metal bin or pan to avoid losing them.

2. Remove the variator wheel attached to the crankshaft by either using an impact wrench to loosen the variator securing nut or jamming a screwdriver into the variator sprocket so that it can't turn freely. With the securing nut loose, pull the variator off the crankshaft axle.

3. Catch the roller weights that are installed behind the variator assembly. Replace them with a new, lighter set obtained from a scooter store. Reinstall the variator assembly back onto the crankshaft assembly by hand, securing the new roller weights.

4. Lock the variator sprocket again with a screwdriver inserted into it to block the sprocket from spinning. Hand-tighten the securing nut until it won't spin any further. Situate a socket wrench and socket on the nut and tighten to factory-specified tightness. Refer to an owner's manual or the manufacturer website if you are not sure about tightness requirements.

5. Place the cover back on the transmission after applying a new transmission cover gasket. Insert the case bolts previously removed. Tighten them again with either a socket wrench or Allen wrench as needed.

Tips & Warnings

• Work with an experienced scooter mechanic if the derestriction is the first time you've work on the engine of your scooter. The process is easy to learn when you see it performed in person.

• Derestricting a scooter will generally make it inconsistent with the local vehicle laws the scooter was sold under. If you are pulled over by a law enforcement officer who notices the differences, your scooter could be impounded or you may end up paying a penalty with a fix-it ticket.

References

• Craig Zone: Scooter De-Restricting
• New Hampshire Scooter Club: How to De-restrict a Derbi Atlantis or GP1
• ScootnFast: Tuning and Modifications

Resources

• Scooterworks: Parts for Scooters