The Alpha moped (72 cubic meters) is the most widespread means of transportation among fans of light motorcycles. This is due to the price of this equipment, its functionality and maintainability. Patency, speed and the small amount of fuel that is needed to drive this vehicle put the Alpha moped (72 cubic meters) in popularity on a par with the most famous Japanese brands. This is no accident, because the engine that stands on these light motorcycles is an exact copy of the Japanese “Cuba” from the company Honda, which is comparable in reliability with the AK-47. Single cylinder engine 139 FMB with a volume of 72 cubic meters. cm works in all weather conditions and does not need frequent repairs and replacement of spare parts. Technical data allows you to use this vehicle in the most extreme conditions, including driving in the cold, on sand and on any terrain. This is the best light motorcycle for Russia. In rural areas, most often you can see exactly the Alpha moped 72 cubic meters. Photos of this model are easily recognizable. Simple and concise design, low price, good speed, maneuverability, maintainability, profitability and a number of other advantages - these are what underlie the reputation of this type of transport.
Unique cross
The record holder for patency among light motorcycles is the Alpha moped (72 cubic meters). The characteristics of its engine, dimensions and weight are very significant advantages. The ability to overcome any off-road at "Alpha" is due to the light weight - 81 kg. To ensure confident movement on sand and dirt, such a lightweight equipment does not need a powerful and heavy motor. If there is a need to overcome a section of deep and viscous mud, steep climb on the sand, or to cross a shallow stream or river, you can always get off a moped and help him cope with a difficult section of the road, pushing him forward like a bicycle.
Due to the thin wheels of Alpha, they can get stuck in the wet sand under the weight of a rider. But without the latter, this moped can be dragged along any off-road, helping it with engine operation in first gear at low speeds. In urban conditions, if necessary, cross the stairs or high curbs Alpha can be lifted just like a regular bicycle. That is why the most remote corners in the forest, on the river bank, which can only be reached by bicycle, are available for this light motorcycle. Many lovers of hunting, fishing and picking mushrooms prefer this particular moped because of its light weight. For heavier and more powerful equipment, driving along a path blocked by a fallen tree in a forest will be an impossible task, but for Alpha there is no problem.
Good speed
The speed ceiling for this moped is 70 km / h, which is quite enough for highway traffic. The weight of the Alpha is small, and handling at higher speeds is noticeably lost. Some fans of this technique try to modify the Alpha moped (72 cubic meters), put a more powerful piston, a zero-resistance filter, stars with an increased gear ratio, modify the ignition system by setting it ahead, and achieve an increase in speed to 90 km / h. But for driving around the city in traffic jams, on country roads, on the ground and gravel, the Alpha speed capabilities are quite sufficient without all these modifications, moreover, with an increase in power and speed capabilities, many important moped components and assemblies begin to wear out.
The Alpha design allows you to install more "solid" engine options on it, bringing its power to 8 liters. from. But “Alpha” with such motors often require repair, the service life of the most important elements of the chassis is noticeably shorter, and they also begin dangerous vibrational damage. A more powerful motor would require an increase in the mass of other structural elements. This would be a loss of many advantages, especially in the cross-country ability and economy that the Alpha moped (72 cubic meters) has. The speed characteristic of these mopeds is perfectly balanced with the lightness and durability of their design and running gear.
Engine
Reliability and unpretentiousness of the 72-cc four-stroke engine “Alpha” is due to its ideal design developed by Japanese experts. Even in a slightly simplified version, with the use of cheaper materials and lower requirements for the quality of components, the 139 FMB engine works surprisingly reliably, which indicates the balance of all its structural elements. The power of this motor is only 5 liters. sec., and the maximum number of revolutions per minute is 7500. However, thanks to a well-thought-out transmission with four gears, the Alpha engine copes with regular loads in all ranges of its gearbox capabilities.
Engine design
The motor design is very simple. There are two valves in the cylinder head - inlet and outlet. Their work is provided by a timing star located in the same place, the rotation of which occurs synchronously with magneto through a chain transmission. On the left side of the engine is a foot shift lever that controls a very simple gear system mounted on two parallel shafts in the crankcase. The oil pump is driven by a timing chain and is located under the crankshaft. On the right side of the engine inside the crankcase there is a clutch unit, which is controlled by a lever using a clutch cable coming from the left handlebar handle.
Prevention and repair of the Alpha engine at home
The engine of the Alpha moped (72 cubic meters), like any vehicle, requires regular maintenance and repair. Regular oil change is an important condition for extending its operation. The oil change process is very simple. The engine warms up, then shuts off, and using the drain hole located under the crankcase, the spent hot oil is easily removed from the crankcase into a specially prepared container. Then new oil is poured. Setting the engine to work properly starts with adjusting the carburetor, with which you can enrich or deplete the mixture. It is also necessary to regularly check the operation of the valves, setting the necessary clearances using a special probe 0.5 mm. Two or three times a season, it is necessary to check the timing of the timing chain , as well as the state of the mechanism of its tension, rubber rollers and dampers. Any damage to the Alpha engine is easily fixed. In case of loss of traction, it is necessary to remove the cylinder head and check the integrity of the valves. Burnout of valves is one of the possible breakdowns of this motor. To restore their performance, it is necessary to clean them and rub them again with paste. This procedure is familiar to many owners of old Lada models. When the timing chain breaks, it is necessary to remove the generator rotor and replace all the elements of the gas distribution mechanism, and when assembling the engine, make sure by the marks that the generator rotor and the timing star are synchronized with the correct cylinder stroke.
The clutch needs to be disassembled and washed once a season in gasoline, since a viscous mixture of oil and metal powder accumulates inside it. With a regular inspection of the engine, the correct setting and replacement of parts with signs of wear 139 FMB will work without fail. Repair of the Alpha moped (72 cubic meters) does not require serious investment and can be successfully carried out with minimal skills at home.
139 FMB Home Power Recipes
The most common way to increase the engine power of an Alpha moped is to replace the piston group with a variant with a large cylinder volume. Typically, such a replacement adds power to the motor, but does not greatly affect the increase in moped speed. There are other ways. The simplest is dual ignition. You can make a step on the protrusion located on the rotor housing of the generator, cutting off a layer of 0.5 mm from half of its metal surface, from the edge that first touches the sensor during the working stroke of the rotor. This will give an increase in power by 5-10%. You can increase the diameter of the inlet and outlet valves. To do this, you need to bore holes in the cylinder head for wider valves, taken from the piston group 139 FMB with a larger cubic capacity. This operation gives an increase in power by 15-20%.
Service and repair of the moped chassis
Repair of the Alpha moped (72 cubic meters) caused by major breakdowns can be completely eliminated by regular preventive replacement of parts that have obvious signs of wear. The chain on the moped should be replaced after each season or after 2,000 kilometers. The chain stretches very significantly, which increases the wear of both stars. Due to the breakdown of the chain at high speed, a situation with a sharp lock of the rear wheel is possible, which can lead to a dangerous fall, injuries and even greater damage to the motorcycle. On the road, such a situation can cause the destruction of the rear wheel tension elements, severe deformation or complete destruction of the tension mounting sockets. Artificial shortening of the chain contributes to the rapid wear of both stars. Tires after 7,000 km completely lose the tread and traction. They need to be changed after 2-3 seasons of operation. The clutch, fuel and brake drum cables of the front wheel should be shortened after each season of operation due to their stretching. The gums in the brake drums are gradually deformed, which increases the play of the wheels. They are also best replaced after each season of operation.
Vibration damage
Some moped failures may be associated with the destruction of its load-bearing elements. The plastic front wing on the Alpha lasts longer than the metal, because it is less susceptible to the negative effects of vibration. The engine mounts on the frame may also break due to vibration. To avoid this, it is necessary to weld wide washers on them. After 2-3 seasons, the battery loses up to 50% of its capacity, therefore its regular replacement is also desirable. Electrical clutch and turn signal control sensors must operate as normal. Both safety during movement and the correct control of gear changes depend on them. Established rear shock absorbers on Alpha wear out, which can lead to unwanted friction of the rear wheel against the inner surface of the rear wing. There are luxury options for the rear shock absorbers for Alpha, which make it possible to put thick tires on the rear wheels, because with them you can slightly raise the back of the motorcycle. With careful handling of fasteners, serious problems with the repair of this moped are unlikely.
Running in
Running a moped "Alpha" (72 cubic meters) does not take much time and has several main conditions for obtaining the correct result. It is necessary to strictly observe the speed limit up to the first thousand kilometers, you cannot overheat the engine, forcing it to work at maximum speeds for more than 20 minutes, and you should also change the oil after 500, 1000, 2000 and 5000 kilometers.
Modifications
Overview of the Alpha moped 72 cc would not be complete without listing its main modifications. There are two frame options for this moped. It is high, with a place for a large gas tank, and low, where the gas tank is small, and above it is the trunk. In terms of their characteristics, both versions of the moped will be almost the same, with the exception of the difference in the volume of gas tanks and a small difference in landing height. “Alpha” is made by a number of Chinese manufacturers, so there are many parallel names for the same model. For example, a moped "Omax Alpha" 72 cubic meters. is a purely Chinese version, and the Orion moped is 72 cubic meters. - Russian assembly of the same model from Chinese spare parts carried out at Velomotors enterprises.
Picking options
Existing modifications of Alpha (72 cubic meters) may differ in some design elements. There are also luxury options for this moped. For example, the Alfa Racer moped is 72 cubic meters. It has a more effective and dynamic seating shape and stands out from the rest of the “Alfs” with spectacular sports contours of the gas tank. In fact, this is the same model of a moped. In luxury versions, hydraulic rear shock absorbers, an alarm system, plastic wings, more attractive decor elements, turn signals and headlights can be installed a little more expensive, an expensive wardrobe trunk and even flip leather bags. But it will still be the same Alpha moped 72 cubic meters, with the same technical characteristics, but 30% more expensive.