The need to repair the carburetor
If you have a Honda, Kvasaki, Navigator scooter or other models of two-wheeled motor vehicles at your disposal, you need to understand the importance of performing periodic carburetor maintenance. The power, ease of starting, pace and control of the motorcycle depend on this system.
In order to ensure that a fuel composition of uniform properties is supplied to the cylinder block, the service of the carburetor should be properly stabilized. Synchronization makes it possible to adjust the volume of fuel and air, which, mixed, flow to the engine.
The most experienced drivers understand that the carburetor on a scooter must not only be adjusted, but also cleaned during service. The fuel contains a certain amount of additives and impurities. When the engine is running, they settle on the walls of the structure, forming blockages in the jets. To enable the carburetor to carry out its functions in full, it is necessary from time to time to clean it from dirt and carbon deposits that have accumulated from the inside.
When is maintenance required?
The carburetor (Keihin PZ30, CVK - not the essence, it is important) of absolutely all common models contains a similar maintenance principle. Therefore, the indicators of the need to perform this procedure in all cases will be similar signs.
The main root cause calling for carburetor adjustment is considered to be uneven engine operation. It is expressed at idle speed. Popping noises coming from the muffler and high fuel consumption may also occur. The driver must pay attention to the appearance of the candles from time to time. Significant changes in their color indicate pathologies in the production of the fuel mixture.
Spark plugs can be considered the main indicator of carburetor service. If they are white, the mixture is lean. Very intense carbon deposits on the candles indicate the production of a rich consistency. This is a divergence from the norm.
The prerequisite may be a carburetor overfilled with contaminants or a malfunction in its settings. In this case, maintenance is performed as quickly as possible. From time to time it is still necessary to clean the system. It depends on how often the motorcycle is used.
Required Tools
Husqvarna special screwdriver
The main tool for adjusting the carburetor of a Chinese chainsaw is a medium-sized slotted screwdriver (flat type). Some saws require special keys, for example to set up the Husqvarna.
For more accurate and faster tuning, a tachometer is still required; it allows you to determine the engine speed, but this is not our case, our task is to learn how to tune by ear.
Read more about what tachometers are available, where to buy, how much they cost, and also how to set up a chainsaw with it.
For reference! This is the same as tuning a guitar. An experienced musician tunes by ear, while a beginner tunes using special instruments. In the case of a chainsaw, the opposite is true. An experienced person adjusts it with a tachometer, and a beginner tunes it by ear. In our repair shop, we use a high-quality and inexpensive tachometer from Aliexpress, which can be purchased at this link.
Buy tachometer on Aliexpress
Disassembling the carburetor
In order to clean the Keihin carburetor, you will need to disassemble it. To get to it, you will need to remove the airbox and gas tank. Then the clamps of the collector pipes are loosened. The suction (enrichment) cable is disassembled.
The Honda scooter and other modifications of similar vehicles have a carburetor system, which are located in the 1st row. They do not need to be separated from each other to clean them. But to change the seals you will need to disassemble the ruler. During disassembly, the carburetor block is removed, as well as the throttle cables.
Now it is possible to simply service the system. The top covers should be removed (the screws are unscrewed). Then you need to inspect the condition of the gaskets, needles and rubber bands. The insides and the carburetor itself, as well as the components around it, should be thoroughly cleaned. A bath of gasoline and an ordinary paint brush are suitable for this.
Synchronization
After cleaning, the Keihin carburetor needs to be adjusted. You can start with synchronization. This is a simple procedure. But it will require a synchronizer. This device checks rarefaction.
The motorcycle must be warmed up to engine operating temperature. Next, remove the tank and filter. The synchronizer will help establish the same vacuum in the collector. The device connects to it. The engine starts.
According to the sensor readings, the valves need to be adjusted. They should respond (but not strongly) to changes in sparseness. If the synchronizer arrow does not perceive changes, the valve must be released. The process is carried out using the corresponding screws on the carburetor. First, adjust the right and left screws. Only after this can the central lever be adjusted.
Removing the carburetor
If it is necessary to dismantle the carburetor block, the next step will be to disassemble the intermediate plate between them and the air filter. Then you should remove the bolts on the bar that holds the block together. Keihin CVK or another model, as a rule, requires the use of impressive physical effort. Most likely, you will need to use a screwdriver with a T-shaped handle. Then you need to disconnect the return spring. To do this, the bolts are also unscrewed in certain places. The plate will simply slide off and detach from the installation.
The carburetors are secured to each other by a long bolt. It should also be disassembled. It is allowed to dismantle the unit. The first carburetor is removed and the spring is put aside. It is forbidden to mix them up (they differ in size). Then the outside of the housing is cleaned.
What to do if you have no experience and can’t adjust it yourself?
Due to lack of experience, adjusting the chainsaw may not work the first time, the saw will begin to work unstably, and starting the engine will be difficult. In this case, you need to repeat everything all over again, setting the adjusting screws to the initially recommended position (written at the beginning of the article, immediately after flushing the carburetor) and then follow the steps of the “Step-by-Step Instructions”.
For reference! Chinese carburetors are cheap and cost 1000-1500 rubles (you can look at how much it costs for your saw on Yandex.Market), some people come to the conclusion that it is easier to buy and replace, in the hope that it comes already configured and screwed on factory settings are set. This opinion is erroneous; any carburetor needs to be adjusted after installation.
Keihin carburetor service
The carburetor on your scooter may require a diaphragm change. In certain cases, it is still necessary to completely change one of the components of the block. The inner metal surface of the device may gradually oxidize. Therefore, you will need to change the aperture. It is pulled out very carefully using a screwdriver. This component can be removed with the dosing needle and flap. Then, if necessary, the previous parts can be changed.
Then you should unscrew the screws of the float chamber. Its cover is removed. You can evaluate the service of the float by simply pressing it. If this component is springy, this means that its operation is reliable. No replacement required. When dismantling, it is important to use screwdrivers of optimal size. All work should be carried out very carefully.
Adjusting the fuel level
The final stage of setup is to check the gasoline level in the chamber. The procedure is simple, but the subsequent operation of the engine depends on its correctness.
The fuel collects in the float chamber. Its volume is checked using a transparent tube. The required parameter can be found in the documentation for the scooter.
The top part of the carburetor is removed. The gasoline level should be just below the low level of the cap. If the readings differ, it is necessary to adjust the stroke of the locking needle by bending the antennae. Having set the desired range, the unit is assembled, the scooter is started and allowed to run for several minutes. After this, the level is checked again.
If the value is saved, the adjustment can be considered completed. The correct setting is checked by sea trials.
Keihin Carburetor Cleaning
After disassembly, the Keihin carburetor will require painstaking cleaning. To do this, you need to get a special one. means. It does not have to destroy the rubber seals. There are a large number of similar cleaners on sale. It is convenient if the product is located in a can. With the help of special tubes it will be easy to spray it over the whole device.
Work should be carried out outdoors. Solvents contain a large number of unsafe components. Therefore, it is not recommended to carry out similar work in a closed building. Under pressure, the carburetor is purged with atmosphere. If necessary, certain areas can be cleaned manually with cotton swabs. If the length of the springs differs significantly (by 1.5 millimeters), they should be changed.
The structure of the scooter and its main components.
The structure of the scooter from the point of view of the organization of its main components can be viewed using the figures below.
The scooter is controlled, as a rule, by three elements: acceleration - 1) throttle; brake - 2) rear and 3) front. Of the two steering handles of the scooter, the gas handle is on the right. Brakes on both sides; rear and front - on the right or on the left, each manufacturer decides for himself how to arrange it.
In addition, the steering panel (so to speak) contains sensors, control buttons and switches (see picture). Usually like this: on the left - horn (1), turn signals (2), low/high beam switch (3); on the right is an electric starter (4), lights on/dimensions/off (5), and sometimes a stop button-switch (you can use it to turn off the engine without turning off the ignition, but you won’t start it until you turn it back on) (6). The number 7 indicates the throttle cable tension regulator. My scooter also has buttons to control the electronic clock. Sensors include a speedometer, sometimes a tachometer, a fuel level sensor; on two-stroke engines there is almost always an oil level sensor in the oil tank, light indicators, and turn signals. Also, scooters with hydraulic brakes usually have a “brake reservoir” (8) on the handlebars, which is used to determine the brake fluid level.
I don’t think there’s any need to explain why there’s an engine in a scooter. The scooter can be equipped with a two-stroke or four-stroke engine - depending on this, the scooter device can be supplemented with additional components, for example, an oil pump for a two-stroke engine. (Well, diesel, rotary and jet engines are not yet installed on scooters. At least not commercially
