All 50 cc scooters supplied to our country are limited in speed at 50 km / h. This is the requirement of traffic rules. But the desire of the owners to make their scooters faster does not disappear. You can achieve higher speed indicators in different ways.
It is necessary
tuning mufflers, CPG kits and others
Remove the stopper. By design, the limiters differ in electronic (limit the speed), mechanical (limit the gear ratio in the variator) and limiters at the inlet and outlet (limit the filling of the cylinder with the mixture). Of course, there are also combined methods. The electronic limiter is rigidly built into the ignition switch and cannot be removed. There is only one way out - buy and install a special sports switch with an adjustable speed limiter or no limitation at all. The first type of commutators is preferable, as it protects the motor from damage when over-spinning.
Replace the muffler on the scooter. Standard factory mufflers from semi-sports scooters (Suzuki Sepia ZZ or Honda Dio ZX) will give a slight increase in engine power without increasing the optimal speed, improve the filling of the cylinder with a mixture, and sharpen the torque characteristic of the engine. Tuning mufflers (for example, LeoVinci SP3) will provide up to 20% increase in power, increase the optimal engine speed. The use of such pipes implies tuning the variator: install lighter weights and a stiffer return spring in it.
Sports mufflers (LeoVinci ZX) provide an increase of up to 50% power, significantly increase engine speed and require not only tuning the variator, but also the use of stiffer return springs of the centrifugal clutch. Or replacing the variator and clutch with sports models. Thus, removing the restrictions and replacing the muffler can increase the speed to 80-90 km / h and improve acceleration dynamics.
Purchase a tuning kit for the engine to further increase power. Well-known companies such as Malossi, Polini, DR, Eurocilindro, produce sets of a piston group of increased volume for 50-cc scooters. The kit consists of a cylinder, a piston with rings and a pin, and a new cylinder head. Installing the kit allows you to raise the engine displacement to standard values of 70 and 85 cc with a simultaneous increase in power at nominal or increased speeds. The most preferred cylinders are nikosil coated, capable of withstanding high rpms, providing more power and torque than steel and significantly more durable.
To prepare the scooter for the competition, install a racing-grade piston group tuning kit (for example, the Polini Kit Corsa). The engine power will increase enormously, but will make it unsuitable for normal everyday use due to moodiness and increased requirements for frequent and expensive maintenance. For example, standard piston rings must be replaced every 10 thousand kilometers, and on the Polini Kit Corsa cylinder every 2-3 thousand.
Install the rear gearbox. Due to the design features of 50cc scooters, a significant increase in engine power does not in itself lead to an increase in maximum speed without changing the gear ratio. Therefore, tuning the engine should always be accompanied by the purchase of a tuning kit for the rear gearbox (for example, Gear-Kit). With the Gear-Kit and the 85cc tuning cylinder, the standard scooter can reach 110-120 km / h. With racing kits, even more.
Go ahead and tune your carburetor. For 50 carburettors with 12mm or 14mm diffuser. After installing the tuning kits on the engine, replace the carburetor with a sports carburetor (eg Dell'Orto) with a 17 or 18 mm diffuser. Racing cylinders require a 22mm carburetor. As a rule, the replacement of the carburetor is accompanied by the replacement of the surrounding installation elements and the installation of a filter of increased performance (zero resistance)