What Are the Best 50cc Chinese Scooter Performance Upgrade Parts?

Within the last few years, a growing performance scooter culture has emerged. Increasing your scooters speed and power can be done in a variety of ways. The 139QMB based 50cc scooters are among the most desirable for those without a motorcycle license endorsement. Larger displacement 150cc performance parts are available on the market, as well.

Light Modifications

Most people who want a simple gain in performance from their Chinese-made scooter will start with tuning their carburetor, add a free-flow intake system and remove any speed-robbing restrictions. Some of these deliberate restrictions on your scooter include an RPM limiter, exhaust restriction ring and/or a small metal collar installed on the crankshaft, designed to limit the scooter's transmission, or "CVT."

Certain Chinese scooters may feature an RPM limiter within the CDI. Racing CDI systems eliminate the RPM limiter and use a more aggressive timing system, allowing your scooter to run faster and with greater efficiency. Running a high-quality iridium spark plug is also important when it comes to squeezing the most efficiency and power from your scooter's ignition system.

Making modifications to the carburetor will yield better engine responsiveness and increase horsepower. When installing a free-flow air filter, you will need to run a larger main jet for the carburetor.

Changing the rollers contained within the CVT variator will affect the scooter's transmission behavior. Using heavier-than-stock roller weights may increase top speed potential, but reduce overall acceleration. Using a lighter roller weights will increase acceleration, while cutting down your scooter's top speed.

Many of these light mods to your scooter will enable speeds of up to 45-50 miles per hour.

Switching your badly worn CVT belt in for an upgraded Kevlar belt will provide better performance and increased reliability.

High-Performance Scooter Modifications

Heavy modifications to your 50cc 139QMB scooter include all of the "Light Modifications" listed above, and even more.

Increasing the engine's displacement using a "big bore kit" will pump massive amounts of power into your Chinese brand scooter. One of the most common and affordable big bore kits increases the engine displacement to 72cc. Bigger kits are available, however the engine's crankshaft bearings may fail prematurely, using kits larger than 72cc.

Many big bore kits feature a high-performance cylinder head, needed to gain the maximum performance from the added displacement. Racing camshafts, performance exhaust and aftermarket carburetors are also available from several Internet sources.

Keep in mind that the scooter will be considered an "off-road" vehicle, or a motorcycle if you install a bore kit larger than 50cc. Fully modified 50cc Chinese scooters have the ability to reach speeds of up to 65-70 miles per hour!

Owners that have heavily modified engines often forget how important it is to upgrade other areas of their scooter. Consider upgrading the tires and brake pads with high performance alternatives. Several manufacturers offer high intensity headlight bulbs and other custom scooter parts that will upgrade the scooter's appearance.