In detail: do-it-yourself scooter repair viper from a real master for the site my.housecope.com.
A list of the most common scooter problems that you can fix yourself without the help of specialists. Crime: the brake light does not light, the brake lever limit switch does not work.
Analytics: one of the brakes is not pressed or there is a malfunction in the brake light circuit.
Action: Replace bulb, adjust brake lever free play, or replace brake lever limit switch.
Crime: blown fuse.
Action: Check and, if necessary, replace the main and starter fuses.
Crime: the junction of the terminal with the wire is covered with a loose coating of oxides.
Analytics: The battery is not producing enough voltage, which can be due to a fault in the circuit or if the battery terminals are oxidized.
Action: check the circuit, recharge the battery if necessary. Clean the terminals from oxides.
A temporary measure is to start the engine with a kick starter.
Crime: you turned on the ignition, pressed the brake lever and the starter button, and the starter relay still does not click.
Analytics: Faulty electric starter circuit.
Actions: clean the contacts on the relay and starter, “ring out” the relay, wiring, starter windings.
Crime: when you press the kick starter lever, it scrolls, but the engine crankshaft does not rotate; the leg does not feel resistance to the movement of the kick starter lever.
Analytics: Kick starter or ratchet gear teeth broke. Action: Replace defective parts.
Crime: the electric starter turns the crankshaft, but the engine does not start.
Analytics: the carburetor is “dry” (unscrew the drain screw of the float chamber - you will see). Variants of reasons: the fuel valve filter is clogged, the gas valve is faulty, the fuel line is clogged, the gas valve control vacuum hose has jumped off or is leaky.
Actions: clean the fuel valve filter, blow out the fuel line, make sure that the automatic fuel valve is working.
Crime: fuel is supplied to the carburetor, but does not enter the pop-up chamber.
Analytics: Fuel float valve sticking.
Action: Remove the float chamber cover and clean the valve seat. If that doesn't work, replace the valve.
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Video (click to play). |
Crime: you unscrewed the candle, and it is “wet” - covered with a layer of unburned benzo mixture.
Analytics: Excessively rich fuel mixture, which is due to too high a level of fuel in the float chamber or due to a clogged air filter.
Actions: after disassembling the carburetor, check the fuel level, clean the air filter.
Side effects: the engine starts immediately if you splash a little gasoline inside the air filter.
Analytics: automatic start-up enricher does not work.
Action: check the health of the starting enricher (there are several ways - they are described in detail in the repair manuals)
Crime: a spark plug unscrewed from its socket does not spark (in a position where the metal part of the spark plug is in reliable contact with the scooter ground).
Analytics: faulty spark plug: broken insulator or electrodes covered with a thick layer of soot.
Action: clean the spark plug with sandpaper or replace. If a spark still does not appear, diagnose other elements of the ignition system.
Crime: a spark is formed on the spark plug, but weak or “running”.
Analytics: the insulator is broken at the spark plug.
Action: Replace spark plug.
2. ENGINE IS DIFFICULT TO START, RUNS UNSTABLE
Crime: the motor does not “spin up”, pops are heard in the carburetor.
Analytics: excessively lean combustible mixture, a possible cause is sucking air through a loose intake pipe or damaged crankshaft oil seals. Water in the float chamber.
Action: replace the gasket under the pipe and evenly tighten the bolts of its fastening. Replace crankshaft seals. Get rid of the water in the float chamber (by unscrewing the drain screw of the float chamber), blow out the jets and carburetor channels, replace the gasoline in the tank.
Crime: a spark on an unscrewed spark plug (in a position where its metal part is in reliable contact with the "mass" of the scooter) is formed, but the surfaces of the insulator and electrodes are dry.
Analytics: automatic starting enricher does not work (if the engine is cold). A normal combustible mixture is not formed. Clogged idle jet.
Actions: check the serviceability of the starting enricher (see point 1). Blow out the jet and carburetor passages.
Crime: on the insulator and electrodes of the unscrewed spark plug, there are drops of water. Analytics: water infiltrated gasoline.
Action: get rid of the water in the float chamber.
Crime: a spark on an unscrewed spark plug (in a position where its metal part is in reliable contact with the "mass" of the scooter) is formed, but the surfaces of the insulator and the electrodes are covered with black oily soot (photo 5).
Analytics: the brand of the spark plug does not correspond to the thermal regime of the engine - its glow number is higher than that required for this engine (the spark plug is “cold”). The temperature in the working area of the candle is insufficient for self-cleaning of the electrodes.
Action: replace the spark plug with a “hotter” one (with a lower glow number).
Crime: the engine starts normally, but soon there are interruptions in its operation and it stalls.
Analytics: the vent hole in the fuel tank cap is clogged or the hoses responsible for communicating the contents of the gas tank with the atmosphere are clogged.
Action: Clean the vent hole in the fuel tank cap or the hoses.
Crime: when you press the kickstarter lever, there is no resistance to the compression of gases in the cylinder.
Analytics: extremely worn piston, cylinder, piston rings.
Actions: check compression - using a compression gauge or by measuring parts (after dismantling the cylinder). When the diagnosis is confirmed, the engine requires repair with the replacement of worn parts.
Crime: the sound of bursting gases is heard, oily traces form on the head and cylinder.
Analytics: Damaged cylinder head gasket or loose head to cylinder.
Action: replace the gasket and tighten the nuts securing the head to the cylinder with the required torque (force) in the order recommended by the repair manual.
3. ANOTHER SOUNDS IN THE ENGINE
Analytics, version 1: increased wear of parts of the cylinder-piston group.
Action: The engine requires repair with the replacement of worn parts.
Version 2: the thermal gap in the valve drive is violated (for 4-stroke engines).
Action: Adjust valves.
Version 3: the chain in the valve drive has loosened (for 4-stroke engines).
Action: Adjust chain tension.
Version 4: grooves have developed in the variator pulley, along which the rollers move, as well as the rollers themselves.
Actions: replace the worn pulley, rollers (possibly other parts of the variator).
4. ENGINE STOPS WHEN THROTTLE IS OPENED SUDDENLY
Circumstance 1: The engine has just been started.
Analysis: engine not warm enough.
Action: continue warming up the engine at idle.
Circumstance 2: The engine is well warmed up.
Analytics, version 1: the carburetor is not adjusted.
Action: adjust the idle speed, if necessary - the main metering system (see paragraph 5).
Version 2: the variator does not work correctly.
Actions: see point 10.
5. ENGINE STARTS NORMALLY BUT IT DOES NOT SPIN
Crime: thick exhaust smoke, excessive fuel consumption, black deposits on the spark plug electrodes.
Analytics: The main dosing system is preparing an excessively rich mixture.
Actions: adjust the quality of the mixture - lower the carburetor throttle adjustment needle one division (groove) down. It may be necessary to install a main fuel jet with a smaller bore.
Crime: the engine overheats, detonation is heard during acceleration, there is a white coating on the electrodes and the spark plug insulator. After turning off the ignition, the engine continues to run for several seconds (detonates).
Analytics: Carburetor's main metering system is leaning too lean.
Actions: adjust the quality of the mixture - raise the carburetor throttle adjustment needle one notch up. It may be necessary to install a large bore main jet.
Crime: the engine runs unusually quietly (although it starts easily), low-smoke exhaust, the engine “does not pull” during acceleration.
Analytics: muffler, channels and cylinder windows clogged with soot (in two-stroke engines).
Action: if possible, clean the carbon deposits. If the muffler is completely clogged (air does not pass), replace the muffler.
6. ENGINE LOSES POWER AFTER LONG DRIVING
Circumstance 1: The engine is air-cooled.
Crime: the movement of air from under the cylinder casing is not felt, and a sheet of paper does not “stick” to the air intake grid (on the right side of the motor) (if you test with paper).
Analytics: the fan blades are broken, another assumption is that the cooling system casings do not fit snugly or are split in places.
Action: Replace the impeller and damaged casings.
Circumstance 2: liquid-cooled engine.
Crime: coolant is leaking, its level has dropped in the tank.
Analytics: system components are faulty: pump, thermostat, radiator.
Action: replace faulty nodes.
7. THE ENGINE DOES NOT ACCELERATE THE SCOOTER TO 50 KM/H
Inspection data: the speedometer is calibrated, the power or speed limiter is not installed.
Analytics version 1: the design of the scooter is not designed for such speed.
Actions: All actions are meaningless.
Version 2: the carburetor is incorrectly adjusted, the muffler is clogged, or the parts of the cylinder-piston group are worn out.
Action: see point 2 or change the scooter.
Version 3: the variator does not work correctly.
Actions: see p.p. 9, 10.
8. SCOOTER DOES NOT START WHEN ENGINE IS RUNNING
Crime: the variator is faulty.
Analytics: the spring of the driven pulley is broken, the V-belt is broken (to verify this, remove the variator cover - breakdowns are perceived at a visual level).
Action: Replace defective parts.
Crime: faulty centrifugal clutch.
Analytics: shoe springs are broken, shoe linings are excessively worn (it is found out during visual inspection after removing the variator cover) (photo 9). Action: Replace defective parts.
9. SCOOTER JERKS
Crime: jerks are felt when driving.
Analytics: CVT belt slipping (due to wear, damage or oiling) or excessively worn pulley surfaces.
Action: replace defective parts (photo 10).
10. SCOOTER ACCELERATES SLOWLY, RIDES SLOWLY
Analytics: During a recent tuning, the weights of the centrifugal governor or the spring of the driven pulley were not chosen correctly. Centrifugal clutch shoe springs are broken or have lost stiffness, centrifugal clutch shoe linings are worn or oily.
Action: carry out tuning more carefully, preferably with the participation of specialists.
In order for the engine of a four-stroke scooter to work perfectly, you need only three things: spark, fuel and compression.When troubleshooting, the following rule should be followed - everything is checked gradually, starting from the most elementary faults and ending with the repair of the main parts of the moped.
The first thing to check is the presence of fuel in the tank and in the system. Then check for spark. The engine will not start if the quality of the mixture is broken, or if the carburetor is clogged.
If the ignition key is not turned, the fuse is blown, or the battery is dead, the engine will not show signs of life. Therefore, before proceeding to a global repair, you should check these reasons.
The starter turns over, but the engine does not start.
Possible reasons - a broken candle, a clogged carburetor, no fuel enters the system.
The engine runs erratically or there is a loss of power.
This may indicate that the carburetor is clogged, the oil or air filter is clogged, the head valves are misaligned, the variator or piston group is worn out.
There was a specific knock in the engine during operation.
This may be a sign that the bearings have failed and need to be replaced. It may also be due to the need to adjust the valve clearance.
- We remove the engine from the scooter. We install the scooter as stable as possible. We remove the trunk. We disconnect all wires from the engine and the gas cable from the carburetor. Remove the fuel hose and vacuum filter. Disconnect the rear shock absorber. After the engine is separated from the frame, unscrew the nut on the mounting axis and remove the axis. After removing the engine, it is advisable to wash it.
- Removing the cylinder head. It is necessary to carry out to clean the chamber from soot. In order to remove the head, you must first disconnect all the "extra" parts. Then the chain tensioner bolt and locking bolts are unscrewed. Then we turn the flywheel until the T designation matches the one on the engine housing. We unscrew the bolts on which the cylinder is attached and remove the chain, and then the cylinder head itself.
- Adjustment of valve clearances must be made if a metallic knock appears. The principle of operation is as follows: the cover of the valve mechanism is removed. The mark on the flywheel corresponds to the mark on the engine case. We measure the gap between the adjusting screw and the valve stem. With an increase or decrease in the gap, we adjust by turning the screw.
As practice shows, it is better to entrust the overhaul of the engine to professionals, since there are many nuances that the average driver does not pay attention to, but which in the future can create even bigger problems and then more expensive repairs will be required.
A video about repairing a 4-stroke scooter will introduce you to the main aspects of repair.
This is how I disassemble crankshafts from fifty kopecks, but in this way you can disassemble almost any.
Increase the speed on the Yamaha jog scooter. Features of boring a variator on a Yamaha jog. How to disassemble.
In order for an internal combustion engine to work, it needs three components: fuel, spark, compression. The main slogan of motor mechanics is “miracles do not happen”. It must always be remembered that if, when troubleshooting and scooter repair it turns out that there is a spark, there is compression, fuel comes in, but the engine does not start, this, as a rule, only means that one of these components is actually missing.
Too lazy to give the scooter for repair and pay money for it. Familiar situation. Then it's time to take up repairs with your own hands.
The basic principle of troubleshooting and repairing a scooter is to step by step eliminate the elements of the system, trying to identify the cause of the malfunction in one of them. It is necessary to search and repair strictly sequentially, from the very beginning of the chain to the very end. That is, for example, in the absence of a spark, you should not immediately change the switch.First you need to make sure that the generator is “alive” with us, then test the wiring. Etc.
An important note: if you have a device in front of you, which, according to the owner, “used to work like clockwork”, it makes sense to ask if old gasoline is poured into the tank. A couple of months of storage is enough for gasoline to lose its octane rating to such an extent that it loses its ability to ignite.
It is important to remember that before making a final diagnosis and starting to repair the scooter, you need to make sure that a knowingly working spark plug is installed on it, and the carburetor is also functioning normally.
In addition, you need to know that the correct operation of the engine (even at idle) is closely related to the correct operation of the variator, clutch, as well as the camshaft and valve group. In other words, with normally functioning power, ignition and CPG systems, the problem may be, for example, in the transmission, since the crankshaft torque is directly transmitted to the variator.
When carrying out diagnostics and repairs, it must be remembered that under certain circumstances that led to the need scooter repair, it is necessary to check not a single element, but the entire system. For example, if the carburetor is clogged, provided that the air filter is intact and impregnated, it is necessary to check for dirt in the gas tank and fuel filter. If the scooter has been driving for a long time without an air filter, or with an unimpregnated filter, then everything must be checked: the CPG, the crankshaft and the main bearings.
Below are some of the problems that may occur, as well as the main steps to resolve them. The links indicate the places where you can find information on this item.
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I have a cover held on by two bolts, oil does not drip. Is the sealing rubber on the lid sold?
good video, we look forward to continuing, I’m stuck here on the cover of the generator, I don’t know who and how evo stuck it so hard there, since there is no puller, I have to invent,
I made a home-made puller, tore off two threads for the impeller, tore off bolt 12. the thread along with the nut, and the magnet sits the infection didn’t even crackle :(((
Good video, looking forward to the continuation) +
Super vidos, the first adequate vidos on YouTube will be on the 157th motor. Hooray, comrades)))
I also wanted to ask at what gaps it is necessary to change the rings, CPG, piston, so that you can already understand whether to plan a replacement or is it still possible to ride? Thank you.
Tell me how to distinguish (139qmb) a fake S.E.E from the original, because I look, the prices are different, and very much?! And which is better to choose S.E.E. or MSU?
the rings were worn out. after 10k run, I had a gap of more than 1 mm, put new ones and everything was about 0.25 now 🙂 The maximum speed is about a hundred, it always starts up perfectly, I think to run up to 20k and put a new cpg. True, I don’t know if he will live at all to 20 k) because it’s always about 80 on the speedometer when driving.
Bro, in his second video, you said that you destroyed the freewheel nut, tell me where you can get the same one, which I can’t find anywhere .. there’s nowhere in the shops, pzdts.
The guides are in excellent condition, in vain you wrote them down as worn out, there should always be a thermal gap, on a new head after a run of 2000 km this gap is not less, and with less even the valves stick, on new heads this is clearly visible, you put it - all the valves are under your own weight in guides, after 500 km you disassemble it, you already need to apply force. And besides, if you replace them, you will need to cut the saddles again and unfold the guides themselves, but you will not find anywhere either a reamer or heads for cutting such sizes. Of course, you can buy, but such a kit will cost as much as 10 new heads :)
good day, bro tell me, please, everything is normal, up to 4500-5000 rpm, then choke, viper storm150, what the hell?
I have a 125 cc Chinese scooter, the piston costs 150 cc for the second time the piston wedges, that is, the piston pin.
Can you please tell me on which site or where can I order repair rings and a piston? at the 157 engine itself, it eats a little oil, took it apart and it turned out that I already had a bored cylinder, and there was nowhere to get rings for it ..
“I had to enter the chamfer” that you didn’t understand where you entered it. the vidos is normal (a lot of grammatical errors (little finger, etc.)), for those who do not watch Matveev or Marika will go.
Modern Chinese scooters are clones, where absolutely everything, including electrical equipment, has the same layout and distribution scheme. You may not find the correct wiring diagram for your particular model, however, if you look closely, the diagram from another scooter may perfectly match the location of the electrical appliances. Thus, it is possible to select the required Chinese scooter electrical repair manual.
Click on diagram to enlarge
Help with wiring. I need the turns (4), stop, dimensions, light, instrument lighting and motor signal to work. How to do it directly so that there is a minimum of wires?
See the diagram and what you don’t need to do. It’s simple
Hello. I have such a problem, I turn on the ignition switch, the signal does not work, neither the starter, nor a single device. It starts only from the paw, what is the reason, please tell me.
Thanks guys for the diagram. It really helped. I assembled a completely new wiring.
Guys, tell me what's the matter: I have a Chinese scooter 4tak.50kub. 139QMB The problem is that it fills the candle. the carburetor is new, I changed the piston rings, adjusted the valves and still overflows and fills the candle.
Victor; maybe you have a problem with the vacuum pump under the gas tank. I used to have this.
What can this vehicle offer the owner in return for lost opportunities? Buying a scooter will give you the opportunity to significantly reduce the time spent on the road to and from work. There will be time to communicate with family and friends, there will be additional opportunities for doing household chores. You no longer have to put everything off for the weekend and then meet the new week without having time to relax.
A maneuverable and light vehicle can significantly improve the quality of life, save money, time and nerve cells. And the fact that repairing a Chinese scooter with your own hands can be done simply and inexpensively will add advantages to the scooter in the vehicle market. Yes, and the offer for spare parts is impressive.
Imagine for a moment: you are a city dweller, your friends bought mopeds a long time ago and ride for their own pleasure, and now a decision has been made to acquire an iron friend yourself. When buying, the driver is unlikely to be given a manual on how to repair a Chinese scooter with their own hands, moreover, sometimes they can advise the wrong oil. For example, they gave oil for a two-stroke moped, and you ride a four-stroke. As a result, you will have to repair the chassis, because the scooter will not start. Will have to do a complete disassembly.
Caution when repairing a scooter
But without special equipment, it will not be possible to repair a Chinese scooter with your own hands, you must have at least a screwdriver on hand. First you need to drain the wrong oil, which has stained the internal mechanisms. Next comes the complete disassembly.Such work as removing the carburetor, at first glance, looks very simple. But if the part is removed abruptly, the special nozzle may be damaged. Then you need to loosen the muffler mount, or remove it completely. Most Chinese products are made using plastic soldering.
The carburetor on a scooter is an important part of the engine power system and is responsible for supplying fuel to the engine cylinders. But due to wear and tear, your carburetor may need to be repaired over time.
In this article, we will tell you how to repair the carburetor of a scooter with a 2-stroke and 4-stroke engine with a volume of 50 and 150 cubic meters, and also explain how to install and adjust a new carburetor on a scooter
The content of the article:
- Removing and cleaning the carburetor
- carburettor installation,
- Adjustment (setting) of the carburetor,
- repair video,
- Our production,
In order to remove the carburetor from the scooter, the first step is to remove all the plastic that prevents access to the carburetor (usually you have to remove the seat and the plastic under the seat). Then we disconnect the fuel and oil hoses (there are oil hoses only on a 2-stroke scooter), the contacts of the starting enricher. After that, unscrew the bolts securing the carburetor to the engine.
Now, after the carburetor has been removed, it is necessary to clean its outer surface from dirt and dust. Can be washed in gasoline and wiped with a dry cloth.
The next step is to partially disassemble the carburetor, namely: unscrew the bolts securing the float chamber cover (2 bolts), then carefully remove the float so as not to bend the plate. We wash the cover of the float chamber very carefully from the inside. Now you can start cleaning the inside of the scooter carburetor itself.
2 easy ways to clean your carburetor:
1) Rinse in gasoline, then purge with a compressor with a nozzle in the form of a pointed tip (this will effectively purge all channels).
2) We buy a can of liquid for cleaning the carburetor. Thoroughly clean all channels and carburetor jets. The spray can also replace the compressor, since the liquid from it is supplied under high pressure, which allows you to effectively clean small channels.
When cleaning, special attention must be paid to all channels and jets (we unscrew the jets during cleaning). We also remove the starting enricher and clean its channels. It is not necessary to dry the internal parts of the carburetor. Now we can put on the float and assemble the carburetor in reverse order.
We install the carburetor on the scooter in the following sequence:
- 1) We fix the carburetor in the place of attachment with the engine, put on the air pipe and fix it with a clamp.
- 2) We put the drain hose on the fitting (lower part of the float chamber)
- 3) We install the gas cable in a special bracket. We check that the protrusion on the cable fastening screw coincides with the groove on the bracket. We fix the cable with nuts
- 4) We put on the gasoline hose and fix it with a spring clamp.
- 5) Connect the contacts of the starting enricher.
As you can see, the connection diagram of the carburetor on the scooter is not so complicated. Next, you need to adjust the carburetor.
Carburetor adjustment on a scooter consists of several stages, which include: idle speed adjustment, mixture quality adjustment and float chamber fuel level adjustment.
Setting the carburetor 2t and 4t scooter has no fundamental differences, except that on some carburetor models there may be no screw for adjusting the quality of the mixture and therefore the quality of the mixture has to be adjusted only by adjusting the needle and float in the carburetor of the scooter
It is necessary to carry out idle speed adjustment on the scooter engine warmed up for 12-15 minutes.Adjustment is carried out using the idle screw, which is installed on each scooter and which allows you to achieve stable engine idling. Turning the screw clockwise will increase the speed, while loosening it will decrease it. We warm up the scooter and achieve stable idling by adjusting the screw.
2-stroke scooter carburetor (Honda Dio)
4-stroke scooter carburetor
1 - idle screw, 2 - mixture quality screw
1 - mixture quality screw, 2 - fuel inlet fitting, 3 - fitting for draining fuel from the float chamber, 4 - screw plug of the float chamber.
The quality of the mixture is very important when adjusting the carburetor, because a lean mixture can overheat the engine and lose power, while a rich mixture forms carbon deposits in the combustion chamber.
The quality of the mixture is adjusted using the adjusting screw. The mixture becomes richer when we turn the screw clockwise and leaner when we turn it counterclockwise.
The adjustment scheme looks like this:
- We warm up the scooter for 10 minutes, turn off the engine,
- Tighten the screw to the end clockwise,
- Unscrew 1.5 turns counterclockwise
- We start the engine and turn the screw back another 1/3 turn. Let the engine run for 2 minutes.
- If the speed increases, then unscrew the screw another 1/4 turn counterclockwise. Also let the engine run for 2 minutes.
- Repeat the previous step until the RPM starts to drop (don't forget to let the engine run for 2 minutes before each change)
- If the speed began to fall, then screw the screw clockwise by 1/4 turn.
Thus, stable operation of the engine at any permissible speed is achieved. Ideally, the engine should work well in the position of the mixture quality adjustment screw unscrewed by 1.5 - 2 turns. However, due to wear of engine parts, this range may vary. If the carburetor of your scooter does not have a screw for adjusting the quality of the mixture, then the adjustment must be carried out only by adjusting the position of the carburetor needle. Raise the needle - the mixture is enriched, lower the needle - the mixture is leaner.
By soot on the candle, you can find out about the incorrect adjustment of the quality of the mixture. If the soot on the candle is black and there is a lot of it, the mixture is too rich. If the soot is almost white, the mixture is too white.
The fuel level in the float chamber can be checked using a transparent tube at the bottom of the carburetor. In order for this to be done, it is necessary to unscrew the cream screw, lift the tube towards the top of the carburetor. Now we check the fuel level with the scooter running. It should be just below the protruding skirt where the float chamber cover attaches to the carburetor.
If the level is low or, as it happens more often, too high, then it is necessary to remove the cover and adjust the moment of operation of the locking game by bending the needle holder (small antennae) in a very small range.
It is worth remembering that, if the carburetor malfunctions or its internal elements are dirty, adjusting the carburetor may only temporarily solve the problem.
That's the whole principle of setting up a carburetor on a Chinese and Japanese (Honda, Suzuki, Yamaha, etc.) scooter. Now you can independently repair and adjust the carburetor on a 2t and 4t scooter engine with a volume of 50 and 150 cubic meters.
