DIY viper scooter repair

In detail: do-it-yourself viper scooter repair 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 up, the brake lever limit switch does not work.
Analytics: the lever of one of the brakes has not been pressed or a malfunction has occurred in the brake light circuit.
Procedure: replace the bulb, adjust the brake lever free play or replace the brake lever limit switch.

Crime: fuse blown.
Procedure: check and, if necessary, replace the fuse for the main circuit and the starter circuit.

Crime: the junction of the terminal with the wire is covered with a loose coating of oxides.
Analytics: the battery gives insufficient voltage, which can happen due to a malfunction 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: the electric starter circuit is faulty.
Actions: clean the contacts on the relay and starter, "ring" 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 stroke of the kick-starter lever.
Analytics: Kick starter or ratchet gear teeth are broken. 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 - see). Variants of reasons: the filter of the gas valve is clogged, the gas valve is faulty, the fuel line is clogged, the vacuum hose for the control of the gas valve has jumped off or is leaking.
Actions: clean the fuel tap filter, blow through the fuel line, make sure that the automatic gas tap is in good working order.

Crime: fuel is supplied to the carburetor, but does not enter the pop-up chamber.
Analytics: float fuel valve stuck.
Procedure: remove the float chamber cover and clean the valve seat. If it does not help, replace the valve.

Video (click to play).

Crime: you unscrew the candle, and it is "wet" - covered with a layer of unburned benzo mixture.
Analytics: excessively rich combustible mixture, which happens due to too high fuel level in the float chamber or due to clogged air filter.
Actions: disassemble the carburetor, check the fuel level, clean the air filter.
Side effects: The engine starts immediately if a little gasoline is poured into the air filter.
Analytics: the automatic starting enrichment does not work.
Actions: check the serviceability of the starting enrichment (there are several ways - they are described in detail in the repair manuals)

Crime: a spark does not occur on a spark plug unscrewed from its socket (in a position where the metal part of the spark plug reliably contacts the "mass" of the scooter).
Analytics: the spark plug is faulty: the insulator is broken or the electrodes are covered with a thick layer of carbon.
Procedure: Clean the spark plug with emery paper or replace. If the spark still does not appear, diagnose other elements of the ignition system.

Crime: the spark on the spark plug is formed, but weak or "running".
Analytics: the spark plug has a broken insulator.
Action: replace the spark plug.

2. THE ENGINE STARTS WITH LABOR, RUNNING UNSTABLE
Crime: the engine does not "spin", there are pops in the carburetor.
Analytics: excessively lean fuel mixture, a possible cause - air is sucked in through a loose intake manifold or damaged crankshaft oil seals. Water in the float chamber.
Procedure: replace the gasket under the branch pipe and evenly tighten the bolts of its fastening. Replace the crankshaft oil seals. Get rid of the water in the float chamber (by unscrewing the drain screw of the float chamber), blow out the jets and channels of the carburetor, replace the gasoline in the tank.

Crime: a spark on an unscrewed spark plug (in a position where its metal part reliably contacts the "mass" of the scooter) is formed, but the surfaces of the insulator and electrodes are dry.
Analytics: the automatic starting enrichment does not work (if the engine is cold). Normal combustible mixture does not form. The idle air jet is clogged.
Actions: check the serviceability of the starting concentrator (see item 1). Purge the carburetor jet and channels.

Crime: there are water droplets on the insulator and electrodes of a twisted spark plug. Analytics: water penetrated into gasoline.
Action: get rid of water in the float chamber.

Crime: a spark on an unscrewed spark plug (in a position where its metal part reliably contacts the "mass" of the scooter) is formed, but the surfaces of the insulator and electrodes are covered with black oily soot (photo 5).
Analytics: the brand of the spark plug does not correspond to the thermal mode of the engine operation - its glow rate is higher than that set for the given engine (the spark plug is "cold"). The temperature in the working area of the plug 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 work 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 to the atmosphere are clogged.
Procedure: Clean the fuel tank cap vent or hoses.

Crime: when you press the kickstarter lever, there is no resistance to compression of gases in the cylinder.
Analytics: the piston, cylinder, piston rings are extremely worn out.
Actions: check the compression - using a compression gauge or by measuring the parts (after dismantling the cylinder). Upon confirmation of the diagnosis, the engine requires repair with replacement of worn parts.

Crime: the sound of escaping gases is heard, oily traces are formed on the head and cylinder.
Analytics: the gasket under the cylinder head is damaged or the fastening of the head to the cylinder is loose.
Actions: replace the gasket and tighten the nuts securing the head to the cylinder with the required torque (effort) in the sequence recommended by the repair manual.

3) EXTRAORDINARY SOUNDS IN THE ENGINE
Analytics, version 1: increased wear of parts of the cylinder-piston group.
Action: the engine requires repair with replacement of worn parts.
Version 2: the thermal clearance in the valve drive is broken (for 4-stroke engines).
Action: adjust the valves.
Version 3: Loose chain in the valve drive (4-stroke engines).
Action: adjust the chain tension.
Version 4: grooves in the variator pulley have developed, along which the rollers move, as well as the rollers themselves.
Actions: replace the worn pulley, rollers (possibly other variator parts).

4. ENGINE STOPS AT SHARP OPENING OF THE THROTTLE
Circumstance 1: The engine has just started.
Analytics: the engine is not warm enough.
Action: continue warming up the engine at idle speed.

Circumstance 2: The engine is well warmed up.
Analytics version 1: carburetor not adjusted.
Actions: adjust idling speed, if necessary - the main dosing system (see item 5).
Version 2: the variator does not work properly.
Actions: see item 10.

5. THE ENGINE STARTS NORMALLY BUT IT DOESN'T SPIN
Crime: thick smoke in the exhaust, excessive fuel consumption, black plaque on the spark plug electrodes.
Analytics: The main dosing system prepares an overly rich mixture.
Actions: adjust the quality of the mixture - lower the carburetor throttle adjusting needle one notch (groove) down. It may be necessary to install a smaller bore main jet.

Crime: the engine overheats, detonation is heard during acceleration, white bloom on the electrodes and spark plug insulator. After turning off the ignition, the engine continues to run for a few seconds (detonates).
Analytics: The carburetor's main metering system is preparing an overly lean mixture.
Actions: adjust the quality of the mixture - raise the carburetor throttle adjusting needle one step up. It may be necessary to install a large bore main fuel jet.

Crime: the engine runs unusually quietly (although it is easy to start), low-smoke exhaust, the engine “does not pull” during acceleration.
Analytics: muffler, channels and cylinder windows clogged with carbon deposits (in two-stroke engines).
Action: clean carbon deposits if possible. If the muffler is completely clogged (no air flow), replace the muffler.

6. AFTER A LONG DRIVE, THE ENGINE LOSES POWER
Circumstance 1: an air-cooled engine.

Crime: no air movement is felt from under the cylinder casing, and a sheet of paper does not "stick" to the air intake mesh (on the right side of the engine) (if a test is carried out with paper).
Analytics: the fan impeller blades are broken, another assumption is that the shrouds of the cooling system are loose or split in places.
Procedure: Replace the impeller and damaged covers.

Circumstance 2: Liquid-cooled engine.
Crime: coolant leaks, its level in the tank has dropped.
Analytics: faulty components of the system: pump, thermostat, radiator.
Action: replace faulty components.

7. ENGINE DOES NOT ACCELERATE THE SCOOTER TO 50 KM / H
Inspection data: speedometer calibrated, no power or rev limiter installed.
Analytics version 1: The scooter is not designed for this 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.
Actions: see item 2 or change the scooter.
Version 3: the variator is not working properly.
Actions: see p. 9, 10.

8. WHILE THE ENGINE IS RUNNING THE SCOOTER DOES NOT START FROM THE PLACE.
Crime: the variator is faulty.
Analytics: the driven pulley spring is broken, the V-belt is torn (to make sure of this, remove the variator cover - breakdowns are perceived at a visual level).
Action: replace defective parts.

Crime: faulty centrifugal clutch.
Analytics: the springs of the shoes are broken, the linings of the shoes are excessively worn out (found out during a visual inspection after removing the variator cover) (photo 9). Action: replace defective parts.

9. THE SCOOTER RIDES IN SPECTS
Crime: jerks are felt when driving.
Analytics: the variator belt slips (due to wear, damage or oiling) or the surfaces of the pulleys are excessively worn out.
Action: replace defective parts (photo 10).

10. SCOOTER SPEEDS SLOWLY, RIDES SLOWLY
Analytics: during the recent tuning, the weight of the centrifugal regulator weights or the spring of the driven pulley are incorrectly matched. The springs of the centrifugal clutch shoes are broken or have lost their rigidity, the linings of the centrifugal clutch shoes are worn or oiled.
Actions: carry out the tuning more thoroughly, preferably with the participation of specialists.

In order for the engine of a four-stroke scooter to work perfectly, only three things are needed: spark, fuel and compression.When troubleshooting, you should adhere to the following rule - everything is checked gradually, from the most elementary malfunctions to 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 we check for a spark. The engine will not start if the quality of the mixture is disturbed, or if the carburetor is clogged.

If the ignition key is not turned, a fuse is blown, or the battery is discharged, the engine will show no signs of life. Therefore, before proceeding with a global repair, you should check these reasons.

The starter motor cranks, but the engine will not start.

Possible reasons - the spark plug is broken, the carburetor is clogged, the fuel does not enter the system.

The engine runs erratically or a loss of power is felt.

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 could be a sign that the bearings are out of order and need to be replaced. It may also be associated with 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. Disconnect all wires from the engine and the throttle cable from the carburetor. Remove the gas hose and vacuum filter. Disconnect the rear shock absorber. After the engine has been separated from the frame, unscrew the nut on the mounting axle and remove the axle. After removing the engine, it is advisable to wash it.
Removing the cylinder head. It is necessary to do to clean the chamber from carbon deposits. 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 body. We unscrew the bolts on which the cylinder is attached and remove the chain, and then the cylinder head itself.
Valve clearances must be adjusted 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 is related to the mark on the engine housing. We measure the clearance between the adjusting screw and the valve stem. When increasing or decreasing the gap, we adjust by rotating the screw.

As practice shows, it is better to entrust the engine overhaul to professionals, since there are many nuances that an ordinary driver does not pay attention to, but which in the future can create even greater problems and then more expensive repairs will be required.
A video on repairing a 4-stroke scooter will introduce you to the main aspects of repair.

This is how I disassemble crankshafts from fifty dollars, but this way you can disassemble almost any.

We increase the speed on the Yamaha jog scooter. Features of boring variator on 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 the motor mechanic 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 usually means only that some of these components are actually missing.

Too lazy to give the scooter for repair and pay money for it. Familiar situation. Then it's time to take on the repair with your own hands.

The basic principle of troubleshooting and repairing a scooter is to exclude system elements step by step, trying to identify the cause of a malfunction in one of them. Search and repair must be carried out 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 we have a "live" generator, 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 a clock”, it makes sense to ask if old gasoline is poured into the tank. A couple or three months of storage is quite enough for gasoline to lose its octane number to such an extent that it has lost the ability to ignite.

It is important to remember that before making the final diagnosis and starting the repair of the scooter, you need to make sure that a working candle is installed on it, as well as the carburetor is functioning normally.

In addition, you need to know that the correct operation of the engine (even at idle) is closely tied to the correct operation of the variator, clutch, as well as the camshaft and valve group. In other words, with normally functioning power supply, 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 some 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 if there is any 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 untreated filter, then everything must be checked: the CPG, the crankshaft and the main bearings.

Below are some of the problems that you may encounter and the basic steps to take to fix them. The links indicate the places where you can find information on this item.

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my lid is held by two bolts, no oil drips. Is the sealing elastic on the lid sold?

good video, we are waiting for the continuation, I got stuck on the generator lid, I don’t know who and how he wrote it there so much, since there is no puller, I have to invent,

made a homemade puller, tore off two impeller threads, tore off bolt 12. thread together with a nut, and the magnet sits, the infection did not even crunch: (((

Good video material, I'm waiting for the continuation) +

Super vidos, the first adequate vidos on YouTube will be on the 157th motor. Hurray, comrades)))

I also wanted to ask, at what clearances do you need 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) fake S.E.E from the original, because I look, the prices are different, and very much ?! And what 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, I put new ones and all the rules were about 0.25 🙂 The maximum speed is about a hundred, it always starts up perfectly, I think to run up to 20k and put a new cpg. The truth is, I don't know if he will even live to 20 k) because always when driving about 80 on the speedometer.

Bro, in his second vidos, he said that he destroyed the freewheel nut, tell me where you can get the same one, I can't find it anywhere .. in the shops there is nowhere, pzdts.

The guides are in excellent condition, you shouldn't have written 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 no less, and even if the valves are less, they even stick, on new heads it is clearly visible, you put all the valves under your own weight in guides, after 500 km you disassemble it already you need to apply force. And besides, if you replace them, you will need to cut the saddles back and unfold the guides themselves, only you will not find any reamers or heads for cutting of such sizes anywhere. Of course, you can buy, but such a kit will cost like 10 new heads :)

Good day, bro tell me, please, everything is normal, up to 4500-5000 rpm, continue to choke, viper storm150, what the hell?

I have a 125 cc Chinese scooter, the piston is 150 cc for the second time the piston wedges, then the piston finger.

Can you please tell me on which website or where can I order repair rings and a piston? at the very 157 engine, a little bit eating oil, disassembled and it turned out that I already had a bored cylinder, and there was nowhere to take rings for it ..

"The chamfer had entered" that where you entered and did not understand. vidos is normal (there are a lot of grammatical errors (little fingers, etc.)), those who do not watch Matveeva or marika will go.

Modern Chinese scooters are clones, where absolutely everything, including electrical equipment, has the same layout and distribution scheme. Perhaps you will not find the necessary electrical circuit for your particular model, however, if you look closely, the circuit from another scooter may ideally match the location of electrical appliances. Thus, you can choose the necessary Chinese scooter electrical repair manual.

This scheme intended for all chinese scooters similar models Lifan LF50QT-15, Lifan LF50QT-8A / 9, Viper Booster, Viper Race, Viper Grand Prix, Viper Phantom, Reggy Bizon and etc.

Click on the diagram to enlarge

The diagram shows all electrical appliances, and also shows all electrical wiring in color, in the same way as it is defined directly on the scooter.

Help make the wiring. I need the turns (4), stop, dimensions, light, t instrument illumination and motor signal to work. How to do what in a straight line so that there is a minimum of wires?

See the diagram and what you shouldn't 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 is started only from the foot, what is the reason, please tell me.

Guys thanks for the circuit. 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 floods the candle. the carburetor is new, changed the piston rings, adjusted the valves and still fills and fills the candle.

Victor; maybe you have a problem with the vacuum pump under the gas tank. I had this once.

What can this vehicle offer to the owner in return for the lost opportunities? Buying a scooter will give you the opportunity to significantly reduce the time spent on the road to the place of work and on the way back. There will be time to communicate with family and friends, there will be additional opportunities for doing household chores. No longer will you have to put off everything for the weekend and then meet the new week without having time to rest.

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. And the offer for spare parts is impressive.

Imagine for a minute: you are a city dweller, your friends bought mopeds long ago and drive for pleasure, and now the decision has been made to get an iron friend yourself. When buying, the driver is unlikely to be given a guide on how to repair a Chinese scooter with his own hands, moreover, sometimes they can advise the wrong oil. For example, they gave oil for a two-stroke moped, and you drive a four-stroke. As a result, the chassis will have to be repaired because the scooter won't start. We'll have to carry out a complete disassembly.

Caution when repairing a scooter

But without special equipment, it will not work to repair a Chinese scooter with your own hands, you need to have at least a screwdriver at hand. First you need to drain the unsuitable oil, which has stained the internal mechanisms. Further, a complete disassembly begins.Work such as removing the carburetor looks very simple at first glance. But if the part is removed abruptly, the special pipe may be damaged. Then you need to loosen the muffler mount, or remove it completely. Most of the Chinese products are made with plastic soldering.

The carburetor on a scooter is an important part of the engine's power system and is responsible for supplying fuel to the engine's cylinders. But due to the wear of the parts, over time, your carburetor may need to be repaired.

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,
Installing the carburetor,
Adjustment (tuning) 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, we 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 off 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 float chamber cover itself 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) We wash it in gasoline, then we purge using a compressor with a nozzle in the form of a pointed tip (this will effectively purge all channels).

2) We buy a can with a liquid for cleaning the carburetor. Thoroughly clean all channels and nozzles of the carburetor. Balonchik also replaces the compressor, since the liquid is supplied from it under high pressure, which makes it possible to effectively clean the 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 concentrator and clean its channels. It is not necessary to dry the inside of the carburetor. Now we can put on the float and assemble the carburetor in the 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 secure it with a clamp.
2) We put on the drain hose on the fitting (the lower part of the float chamber)
3) Install the throttle 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 secure it with a spring clamp.
5) Connect the contacts of the starting enrichment.

As you can see, the connection diagram for the carburetor on a scooter is not that complicated. Next, you need to adjust the carburetor.

Adjusting the carburetor on a scooter consists of several steps, which include: adjusting the idle speed, adjusting the mixture quality and adjusting the fuel level in the float chamber.

The carburetor setting of a 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 adjust the idle speed on the scooter engine warmed up for 12-15 minutes.The adjustment is carried out using an idle screw, which is installed on each scooter and which allows the engine to run smoothly at idle speed. When the screw is tightened clockwise, the revolutions increase, when unscrewed, it decreases. We warm up the scooter and achieve stable engine idling by adjusting the screw.

2-stroke scooter carburetor (Honda Dio)

4-stroke scooter carburetor

1 - idling screw, 2 - mixture quality screw

1 - screw of mixture quality, 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 with a lean mixture, the engine can overheat and lose power, and with a rich mixture, carbon deposits form in the combustion chamber.

We adjust the quality of the mixture using the adjusting screw. The mixture is enriched if we turn the screw clockwise and depleted when we turn it counterclockwise.

The adjustment scheme looks like this:

We warm up the scooter for 10 minutes, turn off the engine,
We tighten the screw all the way clockwise,
Unscrew 1.5 turns back counterclockwise
We start the engine and turn the propeller back another 1/3 turn. Let the engine run for 2 minutes.
If the revolutions increase, then unscrew the screw another 1/4 turn counterclockwise. We also let the engine run for 2 minutes.
Repeat the previous step until the rpm starts to drop (remember to let the engine run for 2 minutes before each change)
If the revolutions began to fall, then turn the screw clockwise by 1/4 turn.

Thus, stable operation of the engine is achieved at any permissible speed. Ideally, the engine should work well in the unscrewed position of the screw for adjusting the mixture quality by 1.5 - 2 turns. However, due to wear of engine parts, this range may change. If the carburetor of your scooter does not have a screw for adjusting the quality of the mixture, then the adjustment should 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 the soot on the candle, you can find out about the incorrect adjustment of the quality of the mixture. If the carbon deposits on the candle are black and there is a lot of it, the mixture is too rich. If the carbon is almost white, the mixture is too white.

The fuel level in the float chamber can be checked with a transparent tube on the bottom of the carburetor. In order for this to be possible, 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 engine running. It should be located just below the protruding skirt where the float chamber cover is attached to the carburetor.

If the level is low or, as is often the case, too high, then it is necessary to remove the cover and adjust the moment of triggering of the locking game by bending the needle holder (small tendril) 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 tuning the 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.

DIY repair of a vacuum tap on a Chinese 4-stroke 50cc Super Sport Acar scooter with an engine 139QMB It's already March. The season is coming soon and it's time to take up the scooter again (Super Sport Acar scooter and the history of its recovery). From the fall, it remains to bring to mind the fuel system and the kickstarter. On this page, we will talk about a vacuum fuel cock, which did not hold gasoline and was blown through to all ends.You can simply put a manual valve, but the design of the vacuum cock is still more advanced and did not want to give it up, although the design of the manual cock had already been made. To begin with, I took apart the crane. It was not made collapsible, but nevertheless I nevertheless flared the flange fixing the cover with a screwdriver, which, in general, was not difficult - the metal turned out to be soft, fragile. Rolling back will definitely not work, but I already had one thought about this.At autopsy, as expected, the diaphragm was torn. Shops with spare parts for the scooter are far away and it was necessary to do with the materials at hand. The farm found a used diaphragm (gas-resistant, elastic, thin rubber needed) from the launcher's carburetor, from which I cut out a suitable size for vacuum cock... Then I assembled the faucet. To achieve the tightness of the structure, I made a clamp-clamp from a rather thick corner. The compression force is adjusted by the bolt.The design turned out to be clumsy, but this is, one might say, an experimental sample on which the possibility of do it yourself vacuum valve repair using improvised means.When connecting the faucet to the fuel system, to my surprise, the gasoline held just fine, although before mounting it on the scooter, when trying to check it by blowing it with your mouth, it seemed that not everything was so tight and the faucet would just slightly let some gasoline through when it was not working engine. But to my delight, the fears were not confirmed. After several test runs of the engine, I still have problems with the repaired vacuum cock did not find it.Thanks for the clever idea! I repeated everything except the clamp. I greased the edges of the membrane cut from a piece of oil-resistant rubber with epoxy glue. I assembled everything. I pulled it off for a day with electrical tape. Then I unwound the electrical tape and put it on. It has been working for two weeks. You can say that epoxy does not stick to rubber. She sticks but is afraid of kinks, but the edges do not bend and she is not afraid of gasoline. GOOD LUCK.You are always welcome ... The main thing is that you also got a very good working version ... Entering text symbols of smiles (such as - 🙂 and 😛) into the message are automatically converted into pictures (there must be a space before inserting - you can copy and paste).
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Compact and economical mini-mopeds, commonly referred to as scooters, have flooded the city streets. Owners of this type of equipment have to master the basics of repair, including studying the question of how to change the crankshaft on a scooter. In any case, this procedure is available to everyone, without exception, and does not require special devices and special technical knowledge.Like any other engine, a scooter motor must have a crankshaft. Its task is to convert the reciprocating movements of the piston in the cylinder into rotational and ensure the rotation of the rear wheel axis. The crankshaft on a scooter consists of two massive discs, connected by a connecting rod neck, offset from the axis to the edge of the circle.These discs serve as flywheels and ensure that the shaft rotates evenly in a given direction. From the centers of each of the disks in different directions, the axle shafts, on which the bearings are installed, extend. Conventional ball bearings provide rotation of the shaft. The shaft ends transmit the rotational motion to the generator and gearbox through a clutch.By itself, replacing the crankshaft on a 4t scooter and other models is very rare, since this part is quite durable. However, there are several reasons for a repair - replacement of a part, namely:

tuning lovers change shafts in an effort to change the technical characteristics of the motor;

in the overwhelming majority of cases, removing the crankshaft is necessary to replace bearings and oil seals. It is these parts that are subject to active wear and tear and periodically need to be replaced;

oil leakage, vibration of the motor during operation, loss of power.

Actually, this is where the list of the main factors explaining the need to start repairs ends.Since the scooter is one of the smallest types of vehicles, it doesn't take much effort to repair the scooter's crankshaft. In a garage, with a set of auto repair tools and a workbench at hand, it is quite possible to complete the entire cycle of repair work. In order to remove the crankshaft and remove the bearings from its axle shafts, you need to stock up on simple pullers.The crankshaft on a scooter is, without exaggeration, the central part of it. In order to get to it, it is necessary to remove the motor and free it from all attachments, including: the cylinder, generator, starter, carburetor and oil pump.How to remove a crankshaft on a scooter?The crankshaft is located in the engine block, which consists of two halves. Among motorists, you can hear such a term as "split the engine". It's about separating the engine halves from each other and removing the crankshaft. This is done as follows:

in order to prevent damage to the connecting rod and block, the surface of the connecting rod is wrapped in a rag;

the screws that fasten the halves of the block together (8 pieces) are unscrewed;

if the bearings are badly worn out and the block has already been disassembled, then the halves will easily separate;

if the block is not disassembled, then it is necessary to put on a bar with holes on the crankshaft half-shaft (the central one is put on the crankshaft half-shaft, bolts are inserted into the other two, which are screwed into the thread of the block screws);

with the gradual tightening of the bolts, the opposite half of the block is squeezed out by means of the crankshaft.

As a rule, the bearings remain on the crankshaft axle shafts and can be removed using a puller. The oil seals are firmly fixed in the holders of the block halves. Having picked up a nozzle of the appropriate diameter, which can be replaced by the head of a socket wrench, the oil seals are carefully knocked out.Change bearings on the crankshaftIn order for the replacement of the crankshaft bearings on the scooter to be correct, you must have a vice and a hair dryer. After securing the crankshaft with the axle shaft up, you need to warm up the inner bearing race with a hair dryer to about 100 degrees Celsius. After thermal expansion, the bearing should snap into place without much effort. The bearing is driven up to the stop using a tube of a suitable diameter. A similar procedure is carried out with the bearing of the second axle shaft.Before removing old oil seals from the motor block, mark or memorize their seating depth. New glands are installed in a cleaned dry cage using a piece of tubing or a nozzle of a suitable diameter. On many motors, the right and left oil seals differ from each other in size. This must be taken into account before replacing the crankshaft on a scooter, when buying a new kit. The oil seals must be installed exactly as deep as the old ones.Features of replacing the crankshaft oil seal on a scooterSo, before us is a crankshaft with bearings installed and halves of a motor block with oil seals. It seems that the completion of the work is on its way, but the most responsible and difficult moment is still ahead. People's repair experience suggests the following technology features:

if you just try to insert the crankshaft back into the block, then for sure nothing will come of it;

if the bearings fit too easily into the block landing races, then a new repair with the replacement of blocks is not far off;

the bearing should fit into the block with good interference.To overcome resistance, you should resort to using a building hair dryer. First, you need to heat the bearing seat in the block to a temperature of about 100 degrees Celsius, and only after that start installing the crankshaft;

working with a hairdryer, it is necessary to ensure that the oil seal does not heat up, otherwise it may overheat and melt;

when installing the crankshaft, it is important to monitor the position of the connecting rod so that it does not rest against the block;

after the crankshaft is installed in one half of the block, it is necessary to lubricate the joint with sealant (but very carefully), heat the seat of the second bearing and connect the halves of the block;

you can squeeze them together with a press, vise or screws that hold them together;

it is important that both parts approach each other strictly parallel without distortions;

the crankshaft half-shafts must be lubricated with oil in advance so as not to damage the oil seals.

Several proven rules for renovationOpening the crankcase of any engine is a kind of surgical intervention in the "organism" of a vehicle. Whether the repair will be successful depends largely on the conditions in which the repair takes place. For a successful repair, some rules must be followed.Before disassembling the motor, wash and drain the oil. It is necessary to work on a clean workbench with clean tools. Each removed part must be rinsed with kerosene, wiped and dried. No matter how you rush, before assembly, all parts of the motor must be wiped dry, clean all threaded connections with compressed air.For any repair, you must put the motor assembly instructions in front of you and strictly follow the order. There are no trifles in this matter. Happy renovation.