Motorcycle tuning Minsk - instructions for modernization

In this article we will look at all the stages by which tuning a Minsk motorcycle can occur - the most affordable and popular motorcycle in the USSR. We will reveal the secrets of tuning the Minsk 125 engine, increasing its power, maximum speed, as well as improving its appearance.

Minsk 125 is one of the most popular famous Belarusian motorcycles, which have been produced since 1951. They have proven to be unpretentious, cheap to maintain, and are also famous for their reliable gearbox. This motorcycle is widely used in training and passing exams for category A, as well as in the “ Minsk cross 125 ” version for teaching the basics of motocross in many sections of the country. Minsk's foreign competitor is the Yamaha YBR 125 road motorcycle, which is perfect for beginner motorcyclists.

Tuning Minsk can be divided into two main parts:

Engine tuning Minsk
Appearance tuning

Reduced intake losses

The engine is the main component of any vehicle.
For motorcycles, it is the power unit that provides the basis for the design and shape of the frame and suspension characteristics. Boosting the engine is the main operation of tuning a motorcycle, both as a whole and for individual components. The purpose of boosting is to increase engine power. One way is to reduce intake losses. The first barrier to air supply is the air filter. As a rule, the original air filter on the Minsk is paper, less often nylon or metal. It would be superfluous to clarify that the throughput of such filters leaves much to be desired.

Foam-based air filters used on foreign motorcycles have become widespread. Such filter elements have minimal resistance to air at the inlet, while having good cleaning characteristics. To reduce vibration and noise levels of the air inlet, a receiver is installed between the carburetor and the filter - a container (usually made of plastic) with a volume approximately 10 times larger than the cylinder.

Intake system

But, maximum engine power is impossible without proper tuning of the intake system. It is this that creates the optimal combustible mixture. First of all, we replace the original exhaust valve.

Instead, they install a petal from any foreign motorcycle. It is recommended to grind the inlet hole. Be sure to install another carburetor. It is recommended to use Japanese analogues with a diffuser of 26-28 mm. The air filter should have minimal resistance.

Appearance tuning Minsk

Every Minsk 125 owner has at least once thought about the appearance of his motorcycle. Perhaps we should start by repainting the frame and other parts of the motorcycle. The first thing to do is remove the handlebars, seat, tank, engine, wheels, fork and other parts to leave a bare frame. Sandblast the parts to be repainted or remove the old paint layer using special attachments for an angle grinder/drill. An attachment on a drill for an emery wheel with Velcro is also very effective for this. Be sure to get rid of pockets of corrosion. The next stage is puttying. This is necessary to get rid of deep scratches and level the surface. Parts with a leveled surface are degreased to prepare for priming. Apply primer in 2 layers. The dried soil should be sanded with 400 grit sandpaper. Then we paint it in the color we like in 2-3 layers, followed by a layer of varnish in 3 layers. The metallic color on your Minsk 125 motorcycle will look very impressive.

The next method of tuning Minsk is polishing the engine crankcase to a mirror finish. This procedure can also be done with your own hands using a set of sandpaper with grit from 120-180 to 2500. By sanding the surface of the engine in steps from coarse to finer, you will achieve an ideal matte surface. At the end of this work, use GOI paste, a felt circle and a drill to achieve the final mirror surface. The Minsk motorcycle engine will immediately be transformed!

This procedure applies to the rims, spokes and muffler - this will help them shine in a new way.

New road tires would be a good investment. The new tread pattern is not only effective when driving on wet asphalt, but also looks attractive. Replacing lighting equipment will also appeal to everyone. For example, LED turn signals and brake lights will not only give a modern appearance, but will also reduce the load on the generator, and will also increase road safety when driving at night. Separately, it is worth noting the efficiency of xenon installation. The recommended heat of light is 4300k as it is the most neutral white light, does not cause eye fatigue and provides the best illumination. A useful tuning in Minsk will be the installation of new chrome mirrors, which will also significantly increase riding safety and complement the transformation of the motorcycle. In conclusion, I would like to note that these tuning actions can be carried out selectively at will and combined according to your taste and financial capabilities.

Minsk was perhaps the most widespread and accessible of the motorcycles of the Soviet Union. Produced at the Minsk plant, it enjoyed deserved popularity among motorsports enthusiasts and ordinary citizens for its low price, ease of operation and good maintainability. This unpretentious motorcycle could serve as both the first vehicle for a novice motorcyclist and a workhorse for many residents of cities and rural areas.

The ancestor of the Minsk motorcycle was the motorcycle of the German DKW center, the equipment for the production of which was exported from Germany as reparations in 1945. The production of the first models was established in Moscow, but then by 1951 production facilities were transferred to Minsk. The first motorcycle rolled off the assembly line of the Minsk Motorcycle and Bicycle Plant back in 1951. For more than 60 years of production of motorcycles of this brand, more than 6.5 million Minsk motorcycles have been sold worldwide.

Tuned motorcycle Minsk 125

But this mass-produced motorcycle, like any other equipment, of course, has its certain drawbacks. The main ones include:

The rather weak engine is the most powerful available in the basic version, only 13 hp.
A poorly designed clutch that can slip even after the motorcycle has been driven for a long time.
On early models, the arrangement of the crankshaft bearings was poorly thought out.
Weak braking system.

But this amazing motorcycle provides its enthusiastic owners with ample opportunities to implement tuning ideas. And, although in the basic version, even with the most powerful engine, the Minsk motorcycle could hardly accelerate to 100 km/h, as a result of competently and responsibly carried out tuning from this beloved, but still not very technically advanced product of the Minsk plant, it is possible to make a truly nimble, responsive and fast motorcycle, not much inferior to its expensive foreign counterparts.

Motorcycle styling Minsk 125

Improving the quality of the air-fuel mixture

The formation of the air-fuel mixture in this vehicle occurs in the carburetor. To reduce losses, at this stage the jets and diffuser surface are polished. This kind of tuning of the Minsk motorcycle can be done with your own hands using thick, rigid thread and Goi paste. The amount of fuel mixture entering the cylinder depends on the diameter of the diffuser.

A significant increase in maximum speed can only be achieved by replacing the carburetor. In the 90s, Japanese carburetors, produced at that time in India, were installed on the Minsk. With proper adjustment, the motorcycle accelerated more dynamically and had greater traction at low speeds.

When setting up a carburetor, the parameters specified in the instructions should serve only as a starting point, but not as reference values. Any carburetor is customizable. An important detail is the tightness of the contacting planes: the carburetor and the adapter. The tightness of the connection significantly affects the life of the engine.

Let's start tuning a Minsk motorcycle with our own hands

To increase power we will tune the engine, clutch, ignition system, cooling and exhaust.

Engine tuning in Minsk - adding a few horses

The most powerful engine in the base, as mentioned above, is a maximum of 13 horses. Of course, this is completely insufficient for modern dynamic riding, motocross, and stunt riding (depending on what the motorcycle tuning is for). Modifying the Minsk engine is not very difficult. To increase power, you will have to work on the cylinder and piston of the motorcycle engine. We reduce the combustion chamber by grinding. This increases the compression ratio and engine power. The engine is now suitable for using high-octane gasoline and this will have a positive effect on increasing power.

Reworking the ignition system

The standard ignition system with a very powerful and reliable generator, a contactless ignition system and an electronic switch require modification in terms of additional installation of a device to change the degree of ignition angle advance depending on the engine speed. With the help of such tuning, the Minsk motorcycle engine will run more smoothly and quietly, and its service life will increase significantly.

Motorcycle tuning Minsk

Exhaust tuning for a Minsk motorcycle

How to make a Minsk motorcycle quieter? To improve the power performance of this engine, it is very important to install a resonator in the exhaust system. A resonator is an oscillatory system where vibration energy is accumulated due to resonance with the driving force

A properly selected resonator allows you to ensure that some of the lost working mixture is returned to the cylinder by the time the exhaust window is closed. It is very difficult to find such a device for free sale, because... it was produced in limited quantities and only for cross-country versions of the Minsk motorcycle. But you can make it yourself using drawings available on the Internet.

Tuning the exhaust system on a motorcycle Minsk

Motorcycle tuning Minsk

Cooling system tuning

Increased power as a result of engine tuning will require a more efficient cooling system. It is necessary to purchase and install a more serious radiator.

Clutch modification in Minsk

Now, after engine tuning, the standard clutch will not be able to cope with the increased power in all operating modes of the motorcycle engine. It needs to be improved by replacing springs and discs. It is necessary to cut off a few millimeters of steel from the standard clutch discs and insert three more selected discs into the free space. As a result of this replacement, the clutch will become slightly stiffer in first gear, but overall the motorcycle will gain more dynamics and drive.

Now we can replace the rear wheel sprocket with a similar one, but with fewer teeth, which will add dynamics to the acceleration of the motorcycle. We replace the standard brakes with good disc brakes - do not forget about driving safety. All these measures, if carried out correctly and responsibly, will allow you to increase the power of a 125 cc motorcycle engine from the standard 13 to 20-23 horsepower, which of course will make your iron horse much faster and more interesting. A technically savvy owner can do the tuning of a Minsk motorcycle engine on his own, or you can contact a motorcycle center, where all the necessary work will be carried out not only quickly and efficiently, but also where you can quickly purchase all the parts and elements necessary for tuning a motorcycle.

Exhaust system

This element must be modified if the engine has been tuned. The problem arises due to the fact that the standard muffler is not designed for increased exhaust gas pressure.

As a result, in certain operating modes, the motorcycle engine begins to choke. Optimal mufflers were installed on a motocross motorcycle, but it is now almost impossible to purchase such a part. Such versions have not been produced for more than 20 years, and therefore spare parts for them have not been produced either.

You can make a high-quality muffler yourself. To understand how to make it yourself, let's look at how it works. Using a muffler of a certain shape allows you to create reverse draft. It allows the remaining combustible mixture to be sucked into the engine. A resonator is used for this.

You can make this detail yourself. On the Internet you can find a large number of formulas by which calculations are made. It is important to remember the basic rule - the size of the resonator directly depends on the power of the motor. This kind of motorcycle tuning in Minsk allows you to achieve maximum efficiency and engine response.

Engine tuning

Probably every motorcyclist is a fan of dynamic riding, but the Minsk motorcycle is not particularly designed for this. Therefore, first of all, owners strive to modify the engine. You can easily add a couple of horsepower here.

Typically, cylinder boring is used for this. This way you can increase the compression ratio, and, accordingly, the engine power. Let's take a closer look at how this is done:

The block is ground down by 1.5 mm, the lower edge of the block head is also ground down, also by 3 mm. The motorcycle cylinder is being modified on a lathe;
Increase the size of the outlet and inlet openings;
Install new valves, better than those made in Japan;
The piston is being modified. They take a standard piston and fit it to the modified engine. If you do not have a special lathe, or you are not entirely confident in your abilities, then it is better to give the engine to an experienced lathe.

After such processing, the engine will receive an additional 1-2 hp. But, it is worth considering that it will be more demanding on nutrition; here it needs to fill with gasoline with an octane number of at least 92.

Increase in working volume

One of the most common ways to increase engine power is to increase the displacement. Tuning the Minsk motorcycle engine involves boring the cylinder liners, but no more than the second repair size. Exceeding this standard will inevitably lead to problems with strength and selection of ring and piston sizes. In the end, the result will not justify the costs. As an option, you can completely replace the cylinder with another one of larger displacement, but in this case difficulties with matching the purge channels are inevitable, so this technique should not be considered optimal either.

External motorcycle tuning Minsk

It all depends on your desires and financial capabilities. The most obvious option is to replace the wheel rims. A simple technical operation will immediately transform your motorcycle.

New tuned wheel for a Minsk motorcycle

To improve the appearance, you can install steel leg protection. This will not only make the appearance of the Minsk motorcycle more sporty, but will also increase your safety when operating it. In addition to this, you can repaint the motorcycle, replace the seat, replace the fuel tank, change the shock absorbers, make a sports body kit, or attach luggage bags to it. It all depends on your ideas and available funds.

Tuned motorcycle Minsk 125

Ultimately, if you have a great desire and with a relatively small investment, you can completely transform a Minsk motorcycle with your own hands, turn it into a cross-country, sports, or fashionable road motorcycle. Many people want sports motorcycle tuning, but cross-tuning is better suited to this model. Photos of Minsk tuning for cross

Cross tuning Minsk 125

The Minsk motorcycle is a legendary product of the Soviet and post-Soviet era, one of the most popular two-wheeled vehicles in the CIS latitudes. It is a lightweight vehicle with an engine capacity of 125 cc. cm was very popular and was released in quite a large volume. The secondary market is literally filled with offers for the sale of this motorcycle. It is simple in design and maintenance, unpretentious, fairly cheap, and is perfect for a beginner. All these qualities also attracted individual craftsmen, thanks to whom tuning for the Minsk motorcycle became very popular due to its comparative simplicity and decent results. Thanks to technical tuning in Soviet times, these models participated in sports competitions and cross-country races.

Read more: How to bleed shock absorbers before installing video

Why do you need tuning?

The point of any tuning is, first of all, to customize the vehicle to suit your needs. This applies to both the technical side and appearance. Internal (technical) tuning of a motorcycle involves boosting the engine, changing the suspension and brakes. Refinement of the appearance includes painting, polishing, chrome plating, installation of additional, including aerodynamic body kits. Tuning the Minsk motorcycle, both external and internal, is not only possible, but even necessary. The fact is that when releasing this vehicle, engineers were primarily guided by accessibility and simplicity. And yet, no matter how simple everything may look, Minsk has potential, which means there is room for improvement.

Engine repair

Assembling a Minsk motorcycle engine is the reverse process to disassembly. Therefore, for a clearer idea of the mechanisms, start working with partial disassembly of the motor. Here's a simple procedure:

Any repair or replacement of parts must first be accompanied by order. Therefore, before work, rinse the unit thoroughly in water and detergent.
Remove the sump cover and remove the clutch mechanism.
Remove the cable and return mechanism, disconnect the shaft and remove the support ball.

If the ball is deformed, it is better to replace it with a new one.

Remove all contacts coming from the generator, marking in advance where each one was located.
Now you need to remove the sprocket with the chain on it. Replace the lock washer with a new one, the shed is probably worn out.
Remove the rod from the clutch, then remove the stator by removing it from its mounts.
To remove the rotor from the crankshaft, you need to unscrew the fastener 3 turns and hit the bolt several times while holding the rotor. After removal, do not forget to remove the segmental key.
Unscrew the cylinder head. The gasket must be replaced.
Remove all rings and stoppers from the block. Then remove the finger, placing a wooden block under the cylinder in advance. Be careful, there is a possibility of bending the connecting rod.
Now you can inspect the pistons for chips or cracks. Any defects inside the engine must be eliminated.

In this easy way, you can partially disassemble the motor. If there are knocks or jolts while riding, it is worth doing a complete disassembly according to the motorcycle operation and maintenance book. In many cases, even simple cleaning of individual elements helps. For example, cleaning your carburetor will provide better fuel delivery without contaminating the mixture. Replacing the air filter will provide a significant flow of air into the engine, which will improve the purity of the fuel-air mixture.

Modification of a standard cylinder

The best solution is tuning the Minsk 125 motorcycle with modifications to its standard cylinder. First of all, it is necessary to eliminate possible displacements of the purge and bypass windows. The purging of the fuel mixture in a two-stroke engine depends on their correct position, which directly affects the acceleration dynamics, efficiency and top speed. To do this, excess metal is removed from the liner, previously removed from the cylinder, using a mechanical or hand tool. All work involves raising the window by 2 mm, boring the radius of the curves and rounding the sharp edges. Such internal tuning of the Minsk motorcycle can increase the number of maximum revolutions by 1000.

Let's start tuning a Minsk motorcycle with our own hands

To increase power we will tune the engine, clutch, ignition system, cooling and exhaust.

Engine tuning in Minsk - adding a few horses

So let's get started:

It is necessary to change the overall dimensions of the inlet, bypass and exhaust holes in the cylinder to improve the filling of the gas-air mixture and more dynamic release of burnt gases.
You can replace your original pistons with Japanese ones with improved performance.
A reed valve must be installed at the inlet of the cylinder itself.

Reworking the ignition system

Exhaust tuning for a Minsk motorcycle

Cooling system tuning

Increased power as a result of engine tuning will require a more efficient cooling system. It is necessary to purchase and install a more serious radiator.

Clutch modification in Minsk

Ignition system

The standard Minsk ignition system does not always successfully cope with its tasks. Therefore, it makes sense to carry out the revision carefully and carefully. Just like with Izh Planet 5 tuning, here they primarily work with the ignition timing.

The model has a good generator, as well as contactless ignition with an electronic switch. But, there is no possibility to change the advance angle depending on the operating mode of the moped engine. Therefore, it is recommended to install a device that forms the angle depending on the need at a given time.

You can buy it in a store; a part from any motorcycle with a similar volume will do. The connection is not complicated, so there shouldn't be any problems. The use of such a device allows you to change the ignition timing depending on engine speed. This approach significantly improves engine efficiency and also increases its power.

Flaws

First, let's figure out what shortcomings the motorcycle has, this will allow us to decide what needs to be improved first. In general, many problems are typical for domestic motorcycles, and when tuning sunrise 3m they are faced with the same problems.

The main disadvantages of the motorcycle are as follows:

Low-power engine. The most powerful engine is only 13 hp;
On the earliest models, the placement of the crankshaft bearings was unsuccessful;
Poorly designed clutch;
Weak brakes.

These are the main disadvantages of Minsk. In general, it is worth noting that all of the above can be eliminated with your own hands, significantly improving the performance of the motorcycle.

Motorcycle engine tuning Minsk part 3 or 4

Miyamoto4 months ago

You’re in vain, purely theoretically Minsk can be upgraded to speeds of under 200. It’s just that if you do this, then all that will remain from Minsk is the engine body. And at 160 it will run at full speed, but there’s not much point in doing this. You can just buy a faster motorcycle, that’s how it is , if an engineering genius lives in your head, purely for yourself, make a Minsk that will tear apart 125k and 200k on the highway. But not like they have with shafts assembled on the knee, this is the first thing that will need to be done, lighten the crankshaft and center it as well as possible and install the ignition is adequate, and at that moment it will spin up about 9k revolutions, at the time of lightness of the crankshaft and alignment and normal ignition, you will probably even need a shorter knee, but then there are the classics, but do not install classic pistons, but either find a single-ring piston with purge windows like in a pit, or without them and sharpen 3 windows yourself In general, I’m not much of an expert, but a really powerful device can be made from Minsk, but I repeat, it’s not worth it, it’s light for everything, it’s a sports APR RS 125 which 125 cc has 33 horses, and 175 goes at maximum speed with revolutions over 12k. Therefore, the whole point of boosting the Minsk is to give it the opportunity to spin at high speeds, and not the classic 6-7k, and they say that the forced one dies faster, because most forced Minsks do not affect the crankshaft, which from the factory is crooked and it simply crushes the engine over time, which is why I designated it as a priority, because a normal centered and balanced lightweight shaft will not reduce the lifespan if all parts are installed of high quality and made wisely. I’m wasting away in the garage right now, on mine I maxed out at 120. On a Voskhodov carb and a standard resonator (I mean, which is what most people make according to old books), where in turn I’m thinking of replacing the carb with a large-diameter replica of the Keyhen, and making the resonator longer in order to get a blast closer to high speeds, otherwise it feels like it’s enough mostly at medium speeds and very little at high speeds. Also, I’m thinking about how to make gears 3 and 4 longer. It’s not possible to turn over 10k because of the same resonator, which simply cannot handle such speeds And the whole problem is that whoever does this simply doesn’t review it on YouTube. And all YouTubers, in turn, create Minskis for forest and cross-country. That’s why the emphasis is on traction and you need to climb a lot in the engine for the sake of speed on the track

Basic model device

The MMVZ-3.112 motorcycle model is a further development of the previous Minsk model MMVZ-3.115. The main differences are a new, more comfortable, wide and long saddle (it hinges to the right along the way and can be removed from the frame), brake drums of both wheels increased to 150 mm in diameter, the use of damping elements in the driven sprocket assembly, and the installation of a pendulum fork on silent blocks, the presence of a new yoke on the frame, making it easier to place the motorcycle on the center stand. The rear brake support plate transmits reaction force to the frame not through stops, but through a reaction rod attached to the pendulum. The brake pedal is mounted on a separate bracket rather than on the footrest tube. The diameter of the wheel hubs and the spokes themselves have also been increased. The spokes became shorter, which overall made the wheel more rigid. The comfort of the motorcycle has been slightly improved.

Engine

The engine is single-cylinder, air-cooled and dual-channel return blown. Aluminum alloy cylinder head. The cast iron cylinder liner is pressed into aluminum fins. Advanced finning of the cylinder and head ensures effective cooling in difficult road and weather conditions. The engine runs on a mixture of low-octane gasoline A-76 with almost any type of motor oil. The engine on the MMVZ-3.112 model produced in 1982 developed a power of 12 hp. at 6,300 rpm, in 1986 a new modification appeared - MMVZ-3.112.11 with a derated engine so that the motorcycle could be used not only on highways.

Transmission

The gearbox is four-speed. The gear shift mechanism is foot-operated. Multi-disc clutch in oil bath. The drive to the rear wheel is by chain, with the main drive protected by stamped casings and rubber chain covers.

Chassis

The frame is tubular, closed type. Telescopic front fork with hydraulic shock absorbers, pendulum type rear suspension with hydraulic shock absorbers.

Electrical equipment

Electronic contactless, batteryless ignition system. The headlight and tail light of the MMVZ-3.112 model are identical to those used on the previous model, the electrical equipment of the MMVZ-3.112 is 6-volt (G427 generator, B300B ignition coil). In 1984, model 3.112.1 began to be equipped with 12-volt electrical equipment (generator 43.3701, coil 2102.3705, lighting devices that meet the requirements of European standards), which distinguishes them favorably from the MMVZ-3.112 model. In 1995, the plant announced a new 14-volt flywheel-type alternating current generator with a power of 90 watts.

Selection and preparation

As a basis for a cross-country motorcycle, you can choose a used small-class bike - it is best to choose models with an engine capacity in the range of 125–350 cubic centimeters. The best option would be a road-going Japanese car aged 12–15 years with a well-preserved engine and an intact frame. In addition, you can even choose a Soviet motorcycle - for example, “Voskhod” or “Minsk”. It won't catch the stars from the sky at sporting events, but it will allow you to get a lot of fun from off-road adventures.

The motorcycle will have to be disassembled - you must remove all the components from it, leaving only the frame. It is better to go through the motor, transmission and drive components, diagnosing possible faults and eliminating them before starting assembly. The frame and tank of the future motocross motorcycle should be cleaned of paint, then covered with putty and a new coating applied according to your wishes. After such preparation, you can begin selecting components and gradual assembly.