Flap valve on a motorcycle engine

If a motorcycle or scooter is chosen as a vehicle, then any of its owners will sooner or later encounter such a concept as a petal valve. This small, but very important detail plays a big role in the work of the motor; a number of the most important technical characteristics of the whole unit will curl from it.

The essence of the flap valve

Before answering the question, what is a petal valve, it is necessary to recall the process of operation of a two-stroke engine, during which the backward emission of a combustible mixture takes place. Besides the fact that it increases fuel consumption, the output of the mixture helps to reduce engine power. The flap valve is designed precisely to prevent fuel from entering the carburetor as a result of the reverse movement through the intake duct. Thanks to this mechanism, a mixture that could escape into the atmosphere enters the cylinder. Accordingly, the motor power increases, the consumption decreases.

petal valve

The device and the principle of operation of the valve

The valve is located in the intake manifold between the carburetor and the engine. Most often, it is mounted on a motorcycle unit and is a body made of two detachable halves — a saddle to which the plate-lobes are placed at an angle. The valve seat is made of steel, the material for the petals is glass fiber. A lock of the petal stroke is the body; this is the plate movement limiter. The block on which this part is mounted is a carburetor nozzle. At the moment when the piston of the cylinder moves down to the starting point, the fuel tends to be released into the carburetor. The valve is triggered, the petals tightly close the circuit, and the mixture is sent back to the cylinder. Like any other mechanical part, the valve can become unusable. petal flap on a scooterIt is extremely important to check the technical condition of the valve. What will be the reason for its replacement? First of all, the deformation of the petals - chips, cracks, change in shape. Also, a signal to the purchase of a new valve will be a tight fit of the plates to the seat, because in the presence of gaps the fuel will seep into the carburetor.Serious problems can also be caused by dirt caught in a knot, so care must be taken to keep it clean.

Flap valve on scooter

Most scooters are equipped with two-stroke engines, respectively, a check valve is installed on them. The flap valve is designed specifically for such motors. Such a mechanical assembly is not installed on a four-stroke unit, as they have valves for the distribution of both fuel and exhaust gases. And in the push-pull model, this process controls the resonator. Therefore, for most of the scooters produced, the valve is an important integral part.

Honda flap valve

If on a moped the motor has gone berserk, the thrust has ceased, or it does not start at all, one of the primary tasks is to check the degree of suitability for using such a detail as a petal valve. On a scooter it is very important to monitor the performance of the part, because the slightest breakdown can lead to further serious problems. If it is broken or worn out, tightness is lost, respectively, the fuel enters the carburetor and engine, and from there to the air filter.This can lead to a loss of response to the throttle adjustment. If a valve malfunction is identified, repair as well as node replacement is possible. You can separately purchase the petals and replace those worn with new ones. Or completely change the valve, which is quite simple. It is necessary to dismantle the carburetor by finding the installed part in the nozzle. Then remove the valve. This is a fairly simple process.

Valve operation on various models

Often it depends on the model of the scooter how long the installed flap valve will be. "Honda" stands out because there are practically no problems with this mechanism. This is facilitated by the materials used in the manufacture - rubber for the body, fiberglass for the plates.

petal check valve

On the scooters produced by Suzuki, Peugeot and Yamaha, on the contrary, the part very often becomes unusable, again because of the materials. The plastic case and the metal petals interact badly with each other, over time the saddles are knocked out by the plates, the node ceases to perform its direct function. Therefore, on such vehicles, it is better to tune the valves immediately, as the factory layout will not be enough.Timely replacement of the plates, even if made immediately after the purchase of the scooter, will not allow the broken valve to disable the entire motor. The best alternative to metal petals will be carbonic.

Valve acquisition

Many motorcycle enthusiasts make the valve themselves, but to ensure the durable operation of the part, buying it will be the best way. Virtually any auto parts store will offer the consumer a mechanical unit such as a flap valve.

 petal valve Price

The price for this spare part varies depending on which model it is installed on and what material it is made of. The most expensive is the carbon valve - the price tag for such a mechanism will be 1000-1100 rubles. The cost of one carbon lobe is 200 rubles, which equates to the cost of the entire node, if it is made of metal and plastic. The average cost of a part can be designated as 500 rubles. Comparing prices on various sites selling auto and motorcycle parts, we can conclude that they are almost the same for valves.

Advantages of valve installation

Installing this small and seemingly not very significant part will significantly increase the traction characteristics of the motorcycle engine, the vehicle will be easier to overcome steep slopes. The capacity of the scooter or scooter will be more, it will be possible to drive together where it was impossible to do it earlier. An undoubted advantage will be the fact that the small financial costs of installing the described parts will significantly reduce fuel consumption.

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