How does the cooling system work?

The combustion of fuel in the cylinder of any internal combustion engine produces heat. Part of the burned fuel (about 35%) is used for useful work, i.e. to propel the vehicle, and the rest is converted into heat. If heat dissipation is not sufficiently efficient, the cylinder, piston and mating components overheat and, due to their overexpansion and lubrication conditions, seizure and damage can occur. To prevent overheating, an air or liquid cooling system is used on all engines, regardless of the tack.

Air cooling (AC) in motorcycles

The air cooling system is the simplest, used not only on scooters, but also on most motorcycles. However, unlike motorcycles, in which the front-mounted engine is open to the flow of incoming air, in scooters the engine is shielded by a housing and is located under the seat at the rear, so it cannot be cooled effectively. For this reason, scooters use forced-air cooling with a fan. 

Oil cooling plays an important role in air cooling systems for four-stroke engines, this is achieved by increasing the crankcase area and installing special oil coolers.

How does forced air cooling work?

In forced-air vehicles, the fan impeller is mounted on the right side of the crankshaft. The centrifugal fan blows air under the housing, which shields the cylinder and cylinder head from the outside. Their surfaces are finned for better heat dissipation.

Risks of overheating an air-cooled engine

Air-cooled motorcycle engines can overheat for a variety of reasons, and overheating can cause a number of problems. Some of the dangers of overheating include:

• Reduced engine performance: Overheating can cause a loss of power and a decrease in engine performance.
  Damage to engine components: Overheating can damage pistons, cylinders and other engine components, leading to costly repairs.
• Warping of the cylinder head and cylinder liner: Overheating can cause warping of the cylinder head and cylinder liner, which can result in loss of compression and power.
• Engine seizure: Overheating can cause engine seizure, which can cause permanent damage and require a complete engine rebuild.
• Reduced lubrication: Overheating can cause oil to break down, reducing lubrication and increasing wear on engine components.
• Increased risk of fire: Overheating can cause oil leaks, which can increase the risk of fire.

It is important to be aware of the signs of overheating, such as a high temperature indicator or warning light, and take action to cool the engine if necessary.

Advantages and disadvantages of an air-cooled engine

Air-cooled engines are commonly used in motorcycles and scooters, and have both advantages and disadvantages over liquid-cooled engines.

Pros:

1. Simplicity: Air-cooled engines are simpler in design and typically require less maintenance than liquid-cooled engines.
2. Lightweight: Air-cooled engines tend to be lighter than liquid-cooled engines, which can improve vehicle handling and maneuverability.
3. Economy: Air-cooled engines tend to be cheaper to produce than liquid-cooled engines, which can make them a more cost-effective option.
4. Durability: Air-cooled engines tend to be more durable and can stand up to more abuse than liquid-cooled engines.

Disadvantages:

1. Overheating: Air-cooled engines are more prone to overheating than liquid-cooled engines, which can damage the engine and reduce performance.
2. Limited power: Air-cooled engines tend to have less horsepower and torque than liquid-cooled engines, which can reduce overall vehicle performance.
3. Noise: Air-cooled engines tend to be noisier than liquid-cooled engines, which can be a drawback for some motorcyclists.
4. Lower efficiency: Air-cooled engines tend to be less efficient than liquid-cooled engines, which can lead to lower fuel economy.

It is important to consider a motorcyclist's specific needs and preferences when choosing between an air-cooled engine and a liquid-cooled engine.

Liquid cooling (LC) in motorcycles

Increasingly, scooter engines are being equipped with liquid cooling systems. A special fluid that is antifreeze at low temperatures (-40...-60°C) and boils at high temperatures (+120...+ 130°C) is used as the coolant. They also have lubricating and anti-corrosive properties. Operating the engine using only water (even distilled water) is not acceptable.

How does liquid cooling work?

The liquid cooling system consists of a pump, thermostat, radiator with expansion tank and connecting hoses. Attached to the radiator, located under the lining of the scooter's front cowl, is an electric fan that is activated by a temperature sensor. The centrifugal-type pump is driven via a coupling sleeve from the rotor of the alternator flywheel mounted on the engine crankshaft or from the auxiliary shaft of the transmission. The pump consists of a body, cover, impeller and sealing sleeves.

Advantages and disadvantages of liquid cooling

Liquid-cooled engines are commonly used in high-performance motorcycles and scooters, and have both advantages and disadvantages over air-cooled engines.

Advantages:

1. Temperature control: Liquid-cooled engines use liquid coolant to control temperature, allowing for better performance and less risk of overheating.
2. Power and performance: Liquid-cooled engines tend to have more horsepower and torque than air-cooled engines, which can improve overall vehicle performance.
3. Quieter operation: Liquid-cooled engines tend to be quieter than air-cooled engines.
4. Better fuel efficiency: Liquid-cooled engines tend to be more efficient than air-cooled engines.

Disadvantages:

1. Complexity: Liquid-cooled engines are more complex in design and usually require more maintenance than air-cooled engines.
2. Weight: Liquid-cooled engines tend to be heavier than air-cooled engines, which can affect vehicle handling and maneuverability.
3. Cost: Liquid-cooled engines tend to be more expensive to manufacture than air-cooled engines.
4. Susceptibility to leaks: Liquid-cooled engines are prone to leaks, which can damage the engine and create a fire hazard.

What type of engine cooling to choose?

Both air-cooled and liquid-cooled motorcycle engines have their advantages and disadvantages.

Air-cooled engines tend to be simpler, lighter and more reliable than liquid-cooled engines. They also tend to be cheaper to repair and maintain. However, air-cooled engines are less efficient at dissipating heat, so they may not run as well in hot weather or at high speeds.

Liquid-cooled engines, on the other hand, are more efficient at dissipating heat, allowing them to produce more power and perform better in hot weather and at high speeds. They also tend to be quieter than air-cooled engines. However, they are more complex, heavier and more expensive to repair and maintain.

Ultimately, the choice between an air-cooled engine and a liquid-cooled engine will depend on individual needs and preferences. If you are looking for a simple, reliable and affordable motorcycle, an air-cooled engine may be the best choice. If you want a motorcycle that will perform well in hot weather and at high speeds, or if you value a quieter ride, a liquid-cooled engine may be a better option.

How do I know if my motorcycle's cooling system is working properly?

There are several signs that may indicate that your motorcycle's cooling system is not working properly:

• Overheating: If your motorcycle's engine is running hot, this may be a sign that the cooling system is not working properly. This can be indicated by the temperature gauge on your motorcycle or by the presence of steam or smoke coming from the engine.
• Leaks: If you notice any coolant leaks, this could indicate a problem with the cooling system. Check around the radiator, hoses and water pump for any signs of leaks.
• Low coolant level: If the coolant level in your motorcycle's radiator is low, it may indicate a leak or a cooling system problem.
• Warning light: Some motorcycles have a warning light that comes on when there is a problem with the cooling system. Check your owner's manual to see if your motorcycle has this feature.

It's also a good idea to regularly check the coolant level and the condition of the hoses and clamps. To make sure your motorcycle's cooling system is working properly, you should also have your motorcycle serviced regularly by a professional mechanic.

You should also check the cooling system after a long or hard ride; if you notice any unusual signs, such as steam or boiling coolant, you should stop the motorcycle and wait for it to cool down before checking it.

What are some common problems that can occur in motorcycle cooling systems?

Some common problems that can occur in motorcycle cooling systems include:

• Leaks: The most common problem with cooling systems is leaks. Hoses and connections can become loose or damaged, causing coolant to leak.
• Clogged or dirty radiators: Dust, debris and insects can accumulate in the radiator, reducing its efficiency and causing the engine to overheat.
• Overheating: If the cooling system is not working properly, the engine may overheat, causing damage to the engine and other components.
• Low coolant level: If the coolant level is low, the engine may overheat. A low coolant level can be caused by leaks, evaporation or a malfunctioning water pump.
• Defective water pump: The water pump is responsible for circulating coolant through the engine. If the water pump fails, the engine will not be able to cool properly.
• Defective thermostat: The thermostat is responsible for regulating the flow of coolant through the engine. If the thermostat fails, it can cause the engine to overheat or become too cold.

It is important to catch these problems early and address them before they cause serious engine damage. Regular maintenance and inspection of your motorcycle's cooling system is essential to ensure its proper operation.

If you notice any unusual signs or symptoms, it's best to have your motorcycle inspected by a professional mechanic to determine the cause of the problem and make the necessary repairs.

What to look for when buying coolant?

The best coolant for a motorcycle should have the following characteristics:

• High boiling point and low freezing point: The coolant should be able to withstand high engine temperatures, and be able to prevent freezing at low temperatures.
• Corrosion inhibitors: The coolant should contain corrosion inhibitors to prevent rust and corrosion on internal engine parts.
• Anti-foaming agents: Anti-foaming agents help prevent bubbles in the coolant, which can impede the cooling process.
• High thermal conductivity: High thermal conductivity allows the coolant to absorb and transfer heat more efficiently, keeping the engine at a safe operating temperature.
• Compatibility with gaskets and hoses: Coolant should be compatible with materials used in gaskets, hoses and other cooling system components.
• Longevity: The coolant should have a long-lasting formula to provide long-lasting protection.
• Proper pH balance: Coolant should have a pH balance that is compatible with the internal parts of the engine.
• Ethylene Glycol (EG) or Propylene Glycol (PG) based: Both types of glycols are common in motorcycle coolants and are known for their durability and rust inhibiting properties.

It is important to check your motorcycle's owner's manual for the recommended type of coolant and make sure it is appropriate for your make and model of motorcycle. You should also change the coolant every 2-3 years or as recommended by the manufacturer.