A wide assortment of Chinese scooters is presented on the Russian motor transport markets , which, despite the variety of brands and models, are equipped with only two types of engines - two-stroke and four-stroke.
139QMB Engine History
The largest and most popular category are four-stroke engines, the most popular and famous among which is the 139QMB model. The first 139QMB engine was developed in the 90s by Honda. Ten years later, the development was used by China for the mass production of engines. The final version, after numerous revisions, has become one of the best engines for motor vehicles: today Japan is actively engaged in its purchase and subsequent sale under the Honda brand.
Engine features
The official manufacturer of the engine for scooters 139QMB is Honling Corporation, which equips this engine with motor vehicles not only of its own brand, but also of other brands.
The corporation sells power units to other manufacturers. The motor itself is very recognizable: the features of the 139QMB engine and its markings on the left side of the crankcase immediately make it clear which heart beats on the scooter.
The motor does not have any flaws, it does not require special treatment and calmly suffers a little negligence and negligence. The manufacturer gives a guarantee for its products that extends to the first 5 thousand kilometers. This run of the new 139QMB 4t scooter engine is enough to fully run and grind all the elements and components of the systems.
The total operational
resource of the motor is about 20 thousand kilometers, with the exception of 5 thousand break-in with an average driving speed of 90 km / h. Technical characteristics of the 139QMB engine are not bad: its power is enough for a double full-size scooter.
Analogs - Engine 1P39QMB
Chinese developers have created an analog of the Japanese engine 139QMB - a motor marked 1P39QMB, which in its appearance completely repeats the original. Despite all the similarities, you can still find the differences: the valve clearances of the 1P39QMB are not adjustable. The situation is similar with a carburetor: before direct operation, it requires thorough cleaning and proper adjustment. Chinese copies of 139QMB engines, of course, cope with their task, but their main purpose was to reduce the total cost of motor vehicles. The budget options for scooters are equipped with exactly these versions of engines that are good only for short trips at low speeds.
Before starting operation, a full run-in of the 1P39QMB engine must be carried out. The optimal mode of operation of the motor begins only after 2 thousand kilometers, but after 10 thousand kilometers all its technical characteristics fall, and it loses in dynamics and power.
157QMJ Engines
In addition to the very popular model - 139QMB engines - Honling Corporation also produces other versions of power units, one of which is 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 analogue of 139QMB. In addition, the design features of the model strongly resemble other Japanese mass-produced engines.
The advantage of the 157QMJ is the increased operational resource - about 25 thousand kilometers. The engine boasts powerful dynamics and high maximum speed. However, he has his own minus - too high a price in comparison with previous versions of engines.
Engine D1E41QMB
The D1E41QMB motor is the only Chinese two-stroke engine model. A distinctive feature of this motor from other representatives of the category of power units is the presence in the design of a chain reverse gear. Uninterrupted operation of such an engine is ensured by a mixture of gasoline and oil in the proportions of 40 to 1. The working life of the engine 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.
Engine break-in
Incorrectly run-in engine 139QMB in most cases leads to failure of the piston system. Between the details of the new CPG friction occurs, which leads to an increase in engine temperature.
Running in the scooter motor as follows:
- The scooter is placed on the central footboard.
- Within 5 minutes, the engine starts at idle, the field of which is cooled during the same time.
- The engine also runs for the next 10 minutes, after which it cools for 15 minutes.
- The motor starts up again for 15 minutes, then it is turned off and left to cool for 15 minutes.
- The scooter starts again for 30 minutes, after which it is muffled and left for 20 minutes.
After carrying out such manipulations, you can run the scooter itself. The gas handle in the first 100 kilometers of the path should not be twisted more than 1/3 of its full stroke. The maximum speed should not exceed 30 km / h. At 15–20 km / h, speed can be increased by the next 300 kilometers - during this time the engine should more or less reveal its potential.
After the break-in process, the oil changes without fail.
Engine valves are adjusted every 500 kilometers.
Engine tuning
The first thing they try to change when tuning the 139QMB engine is cubic capacity. For this purpose, the standard piston system is replaced by 82cc. At the same time, a new cylinder head with larger valves is installed. The piston system changes along with the camshaft, because for its correct operation, a greater amount of fuel-air mix is required. The new camshaft will help increase the volume of the incoming fuel mixture, but carburetor replacement will still be required.
Carburetor replacement
A standard carburetor after replacing the elements described above for the further operation of the engine will not work - instead, a budget CVK18 is installed, equipped with an 18 mm diffuser. At the same time, it is advisable to purchase a set of jets of different sizes, since you will have to sweat a lot in order to correctly configure the carburetor.
Air filter
It is not recommended to completely remove the filter element or replace it with a filter of zero resistance - this can lead to contamination of the carburetor. Specialists usually recommend removing the plug that is installed at the inlet to the air filter.
Many reviews that affected the assembly of the 139QMB engine after tuning mentioned installing a zero-resistance air filter. Despite the fact that this solution is one of the most popular, it is not always appropriate and justified.
The reason is that the installation of such a filter leads to 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 jets in the carburetor.
Separately, it is worth noting that a standard carburetor equipped with a 16 mm diffuser is installed together with a 62–72cc piston system, while a 82cc piston system is equipped with a carburetor with an 18 mm diffuser.
For replacement, it is advisable to purchase a set of jets, since several different options may be needed to adjust the carburetor.
Variable speed drive
You can increase the efficiency of a standard scooter variator and use its full potential only after installing an increased belt. At the same time, a set of new weights is being acquired - they should all differ in weight. For the variator, the necessary weight of the weights is very carefully and painstakingly selected, since the maximum speed of the motor vehicle and the dynamics of its acceleration depend on them.
Switch
To carry out scooter tuning, it’s enough to purchase a classic switch without a speed limit. For a four-stroke engine, the best option available on the market will be a special universal switch.
Summary
The 139QMB engine is one of the most popular and sought-after power units for motor vehicles. The listed manipulations with the motor are one of the least expensive and effective tuning options. It is the most appropriate and budgetary, since replacing engine parts with better ones will cost more than acquiring another scooter model with an improved engine.