139QMB (scooter engine): characteristic and device

On the Russian motor transport markets there is a wide range of Chinese scooters, which, despite the variety of brands and models, are equipped with only two types of engines - two-stroke and four-stroke.

History of the engine 139QMB

The largest and most popular category are four-stroke engines, the most popular and known among which is the model 139QMB. The first model of the 139QMB engine was developed in the 90s by Honda. Ten years later, the development was used by China for mass production of engines. The final version after numerous reprocessing has become one of the best engines for motorcycle transport: to date, its purchase and subsequent sale under the brand Honda is actively engaged in Japan.

Engine Features

The official manufacturer of the engine for scooters 139QMB is the corporation "Honling", which equips this motor vehicle with not only its brand, but also other brands. The corporation sells power units to other manufacturers. The motor itself is quite recognizable: the features of the 139QMB engine and its marking applied to the left side of the crankcase immediately make it clear which heart beats at the scooter.

The engine does not have any flaws, it does not require special treatment and quietly demolishes a slight negligence and negligence. The manufacturer gives on the production a guarantee extending on the first 5 thousand kilometers. This run of the new scooter engine 139QMB 4t is sufficient for a full run-in and grinding of all the elements and components of the systems. The total operating life of the motor is about 20 thousand kilometers with the exception of 5 thousand break-in at an average speed of 90 km / h. The technical characteristics of the 139QMB engine are not bad: its power is enough for a two-dimensional full-size scooter.

Analogs - motor 1P39QMB

Chinese developers have created an analogue of the Japanese engine 139QMB - motor with the marking 1P39QMB, which in its appearance completely repeats the original. Despite all the similarities, it is still possible to find the differences: the valve gaps in 1P39QMB are not regulated. A similar situation with the carburetor: before immediate use it requires thorough cleaning and correct adjustment. Chinese copies of engines 139QMB, of course, with their task to cope, but their main purpose was to reduce the total cost of motor transport. Budget scooter options are completed with exactly these versions of engines, which are good only for short trips at low speeds.

Before the start of operation, it is mandatory to carry out a full break-in of the 1P39QMB engine. The optimal mode of the engine starts only after 2 thousand kilometers of run, but after 10 thousand kilometers all its technical characteristics fall, and it loses its dynamics and power.

157QMJ engines

In addition to the very popular model - engines 139QMB - the corporation "Honling" is engaged in the production and other versions of power units, one of which - 157QMJ. It is installed on expensive models of scooters of famous brands. According to its technical parameters and indicators of functionality and reliability, this version is a complete analog of 139QMB. In addition, the design features of the model strongly resemble other Japanese mass-produced engines.

The advantage of 157QMJ is an increased operational resource - about 25 thousand kilometers. The engine boasts a powerful dynamics and high maximum speed. However, he also has his own minus - too high a price in comparison with previous versions of engines.

Engine D1E41QMB

The D1E41QMB is the only two-stroke engine in China. A distinctive feature of this motor from other representatives of the category of power units is the presence in the design of the chain rear transmission. The uninterrupted operation of such an engine is ensured by mixing gasoline and oil in proportions of 40 to 1. The working life of the motor is about 10 thousand kilometers, after which there is a need for repair. The disadvantage of the engine is the forced speed limit - no more than 50 km / h.

Break-in engine

Incorrectly conducted break-in of the engine 139QMB in most cases leads to failure of the piston system. Between the details of the new CPU, friction occurs, which leads to an increase in the temperature of the engine.

Running the motor scooter is as follows:

1. The scooter is placed on the central step.
2. Within 5 minutes the engine starts at idle, the field of which is cooled during the same time.
3. For the next 10 minutes, the engine also works, after which it cools down for 15 minutes.
4. The motor is restarted for 15 minutes, then it is muffled and left to cool for 15 minutes.
5. The scooter starts again for 30 minutes, then it is muffled and left for 20 minutes.

After carrying out similar manipulations it is possible to carry out the running-in of a scooter. The handle of gas in the first 100 kilometers of the road should not be twisted by more than 1/3 of its full stroke. The maximum speed should not exceed 30 km / h. At 15-20 km / h, the speed can be increased by the next 300 kilometers - during this time the engine should more or less open its potential.

After the process of such running-in, oil changes without fail.

The engine valves are adjusted every 500 kilometers.

Engine tuning

The first thing that they try to change while performing tuning of the engine 139QMB, is a cubature. For this purpose, the standard piston system is replaced by 82cc. At the same time, a new cylinder head with enlarged valves is installed. The piston system is changing along with the camshaft, since more fuel-air sweeps are required for its correct operation. The new camshaft will help increase the amount of incoming fuel mixture, however, replacement of the carburetor will still be required.

Replacing the carburetor

The standard carburetor after replacing the above-described elements for the further operation of the engine is not suitable - instead install a budget CVK18 equipped with a diffuser for 18 mm. Simultaneously, it is desirable to purchase a set of jet nozzles of different sizes, since you will have to sweat a lot to correctly adjust the carburetor.

Air filter

Completely remove the filter element or replace it with a zero resistance filter is not recommended - this can lead to contamination of the carburetor. Experts usually recommend removing the plug, which is installed at the entrance to the air filter.

Many of the reviews that affected the engine assembly of the 139QMB after the tuning dealt with the installation of an air filter of zero resistance. Despite the fact that this solution is one of the most popular, it is not always expedient and justified.

The reason lies in the fact that the installation of such a filter leads to a rapid contamination of the carburetor. The main reason for using a zero-resistance filter is the need for a richer fuel mixture after mounting an enlarged piston. However, this can be avoided by installing a new camshaft and replacing the jet nozzles in the carburetor.

Separately it is worth noting that the standard carburetor, equipped with a diffuser for 16 mm, is installed together with a piston system 62-72ss, while the piston 82ss is equipped with a carburetor with an 18mm diffuser.

For replacement, it is advisable to purchase a set of jet nozzles, since several different options may be needed to adjust the carburetor.

Variable speed drive

Increase the efficiency of the standard scooter and use its full potential only after installing an enlarged belt. Simultaneously with it a set of new weights is purchased - they all need to differ in weight. For the variator, the necessary weight of the weights is carefully selected and carefully selected, since the maximum speed of the motor transport and the dynamics of its acceleration depend on them.

Switch

To carry out the tuning of the scooter, it is enough to purchase a classic switch without limiting the number of revolutions. For a four-stroke engine, the optimal option from the proposed on the market will be a special universal switch.

Results

The 139QMB engine is one of the most popular and sought-after powertrains for motorcycles. The above manipulations with the motor are one of the least expensive and effective tuning options. It is the most expedient and budgetary, since replacing engine parts for better ones will cost more than buying another scooter model with an improved engine.