Hello friends! In this article I want to talk about the mechanical clutch of the Alpha moped, its adjustment and malfunctions. Many people adjust the clutch using a cable, but this is not correct.
Stages of self-disassembly and assembly of the Alpha moped engine
The engine of the Chinese Alpha moped has characteristic features, thanks to which fans of motorcycle technology prefer this particular model.
Engine for Alpha moped
Engine capacity - 72 cc. With the right approach, it can be upgraded to 110 cc. Also, if desired, you can increase the speed by 10 kilometers.
The weak point of the engine is the gearbox, which requires close attention and a delicate approach . When repairing the “heart” of a moped, you need to know how to correctly disassemble and reassemble this part of the motorcycle “organism”.
Alpha is equipped with a powerful engine, the circuit of which is complex. If you can’t figure it out on your own, it is recommended to contact an experienced specialist. The price of repairs is quite affordable.
Carburetor Adjustment Tools
It is necessary to prepare a screwdriver with a flat head, with which you will unscrew the bolts. If you have to remove the carburetor to clean it, you will need a 10mm wrench. You will also need a carburetor cleaner. It is available in aerosol form. The cleaner is very caustic, so it is advisable to purchase rubber gloves when working with it.
Carburetor cleaner
Knock in the engine on an alpha moped.
One of the problems motorists face on mopeds is a knocking sound in the engine. There are different types of knocking, but a knocking sound in the engine means that it definitely needs to be repaired.
Causes of engine knocking on a moped:
- The most harmless thing is that your valves are knocking. To check this, you will need (in the simplest version) a screwdriver; it is best to use a medical stroboscope or, well, or a professional one, if you have one. Next, take a screwdriver and apply the handle to your ear, and lean the other end against the engine. And so lean it against each part of the engine and you will be able to approximately position where you are knocking. Valve knocking differs from other knocking sounds in that it is more metallic. It feels like light pieces of metal are hitting each other. If the valves are knocking, the knocking will be louder on a cold engine than on a warm one. Typically, valve clearance decreases as it warms up, so the valves knock louder when cold.
- The timing chain may also be knocking. In lower engine engines, the timing chain cannot knock, because it is not there, there are pushers. They will also knock, but in this engine this is not a breakdown. The timing chain may be knocking because the timing chain tensioner is broken; if it is broken or worn out, the timing chain will start knocking. This is only checked when you disassemble the engine and check the chain. The timing chain can also stretch and the tensioner can no longer tension and the chain begins to knock. There is only one way to check this. Remove the tensioner, then you need to press on it, and if you understand that the chain does not tension when fully pressed, when the tensioner is fully recessed, then the chain definitely needs to be changed.
- The bearings may also be knocking. Bearings can knock in the basket, they can knock in the box. If you heard an engine knock on the right side, then if you depressed the clutch, the knocking stopped, and when you released it, the knocking started again. In this case, your release bearing has died or your clutch basket has simply weakened. Further, if the knocking occurs at idle, or when engaging any gear, then the bearings may be to blame. You will definitely have to disassemble the engine and see if you have worn out bearings, if the seal is broken and if the bearing is intact. If suddenly you experience a knocking noise only when you engage a certain gear, this means that you have a broken tooth on the gear, either a tooth or a hook. This is very bad, under no circumstances should you drive such an engine, because it could jam at one moment.
- The most unpleasant type of knocking that occurs on engines. If suddenly there is an oil starvation or you have driven a huge number of kilometers on this engine, then the crankshaft and connecting rod may lift up. How can one understand such a knock? The knocking sound will be as if throughout the entire engine, as if someone is hammering the crankcase with a hammer. A very sharp, loud sound that does not disappear at any speed. If you hear such a sound, turn off the engine immediately and do not try to continue driving. If your valves or timing chain are knocking, then you can drive to the garage and get it fixed; if the gearbox is knocking, then you can also get there, but it’s not advisable, and if the crankshaft is knocking, then stand still and don’t move.
- Bendix may also knock. When it is produced, it develops a slight imbalance. If you hear a knock from here, then you need to check the bendix.
- What else could a knock mean when you heard such dull knocks, but a grinding sound is added to them? If you heard that grinding and knocking and when you add gas they only intensify, then it means that the crankshaft bearings in your engine have fallen apart. Because in such engines the crankshaft lies in bearings. The main bearings are immediately replaceable.
When to adjust the clutch
In general, there are two cases when you need to think about adjusting the scooter clutch:
Clutch leads
When you press the clutch lever and engage the gear, the moped starts moving (with the clutch depressed).
The clutch is slipping
When the gear is engaged and the clutch lever is completely released, the engine runs at high speeds, and the moped moves slowly or hardly moves at all.
All these problems are the result of a less than ideal design of the clutch release and engagement drive, as well as the fact that the parts of the clutch itself wear out after some mileage, which together leads to such troubles.
Dismantling engines and gearboxes of Alpha mopeds
In order to disassemble the engine you need to do the following:
Remove the screws located in the intake manifold.
Remove all cylinder covers and screws.
Remove the cylinder head.
The gearbox is disassembled to replace parts such as rotors, clutches or cylinders.
In order to disassemble the gearbox you need to do the following:
Remove the retaining ring, then the drive gear is removed.
Unscrew the locking gear screw, then remove the gear shift mechanism itself
Remove the shift fork and shaft, then the crankshaft and drum.
Put everything back to front.
And in conclusion, we would like to say that although the Alfa moped rarely breaks down, it is not worth disassembling and repairing it yourself if you lack knowledge and experience, or you are simply not completely sure that you can handle it, since if you want to save money, you can lose a lot more . Therefore, you should not refuse the services of professionals. But still, if you decide to repair the engine of the Alpha 110 moped yourself, do not forget to use the diagram or training video. And if there is no diagram, then mark the location of the parts on a piece of paper so as not to forget.
Alpha moped engine assembly (part 1)
Alpha moped engine assembly (part 2)
You might be interested in the Alfa 125 cc engine with automatic clutch, tuning
Idle adjustment
There are two ways to adjust the carburetor. It's fast and slow. The slow method is considered the highest quality.
A quick way to adjust idle speed
With the engine running, warmed up and running, use a screwdriver to gradually tighten the quality screw clockwise. We turn the screw until the engine starts to stall.
Next, unscrew the quality screw counterclockwise 2 turns. Use the fuel quantity screw to adjust the engine speed. In summer, on a warm engine, the speed should be 1500 rpm.
If you make the revs lower, then when driving when you let off the gas at speed, the moped will be slowed down by the engine, which is not comfortable.
A high-quality method for adjusting idle speed on a carburetor
With the engine running, use a screwdriver to tighten the speed screw and raise the engine speed to 3500 rpm.
Next, use a screwdriver to adjust the quality screw. We turn it clockwise or counterclockwise until the engine speed reaches its maximum.
We use the quality screw to achieve maximum engine speed and use the speed screw to reduce the speed to 1500 rpm.
Causes of malfunction
The Chinese Alpha moped, whose price is affordable, does not cause owners many problems. Interruptions in a moped engine have several causes, and once you understand them, you can quickly fix the breakdown.
Disassembling the moped engine
So, if the engine starts with great difficulty, the muffler “shoots”, and smoke comes out of the chimney, it means that the moped is “capricious” due to problems with the carburetor. In order to solve this problem with the Alpha moped, you need to:
- clean the carburetor;
- thoroughly clean the moped's air filter;
- tighten the screws;
- adjust the moped carburetor.
Tuning of external parts
By improving the external parameters, you can improve not only the aesthetic appearance of the Alpha moped, but also increase its aerodynamic performance and make movement more comfortable. The following is usually used for tuning external elements:
- Replacing the seat with a wider and more comfortable one.
- Installing protective panels will help prevent leg fractures and protect them from damage.
- Replacing the wheels with wider ones will increase the stability of the moped. This is especially true when replacing an engine.
- Installing a windshield helps improve travel comfort. But at a speed of more than 40 km/h it already begins to affect the aerodynamics of the moped.
- Replacing disks has a more decorative meaning. The standard wheels on the Alpha are also quite drivable.
- Replacing the plug. If the Alpha moped will be used to travel on uneven roads, for example, in the forest or outside the city, you can replace the forks. Strengthening the shock absorbers helps soften the load on the wheel.
- Replacing LEDs can also be a great solution. You should not use xenon diodes, as they will dazzle drivers and will not be better in terms of lighting quality than conventional ones.
If desired, tuning can be completed by styling the moped by performing airbrushing or changing the color of the body. An excellent solution to highlight a moped would be to install LEDs under the fenders or on protective panels.
Tuning an Alpha moped is a very rewarding activity that can captivate the owner in the direction of improving his model. Design and assembly features make it possible to improve Alpha in absolutely any direction. This makes it very convenient for both beginners and experienced hobbyists.
Technical characteristics of the Alfa Romeo 939A5000 2.2 JTS engine
| Exact volume | 2198 cm³ |
| Supply system | direct injection |
| Engine power | 185 hp |
| Torque | 230 Nm |
| Cylinder block | cast iron R4 |
| Block head | aluminum 16v |
| Cylinder diameter | 86 mm |
| Piston stroke | 94.6 mm |
| Compression ratio | 11.3 |
| Features of internal combustion engines | DOHC |
| Hydraulic compensators | Yes |
| Timing drive | chain |
| Phase regulator | on inlet and outlet |
| Turbocharging | No |
| What kind of oil to pour | 5.4 liters 5W-40 |
| Fuel type | AI-95 |
| Ecological Class | EURO 4 |
| Approximate resource | 220,000 km |
The online manual for 1.9 and 2.2 JTS engines is posted here
A lot of useful information has been collected on the Alfisti.ru forum
