TERMINOLOGY FOR MOTORBIKE PARTS AND REPAIRS

The terminology in bold is provided in both English and Vietnamese, making it easier for you to communicate with local mechanics if they don’t understand your explanation. Not all mechanics in Vietnam are familiar with standard technical terminology, as many rely on hands-on experience rather than formal training.

Vietnam Motorbike Rental has put together this glossary to help you describe common motorbike parts and mechanical problems more clearly, making it easier to get the right repairs when something goes wrong during your journey.

A

Air filter (Lọc gió) prevents abrasive particles from entering the engine’s cylinders, where they could cause mechanical wear and contaminate the engine oil. Air filters are part of the engine air induction system (AIS) and are typically made from paper or foam/felt materials.

Air/fuel ratio (Tỷ lệ xăng/gió) refers to the mixture of air and fuel delivered to the engine by the carburetor or fuel injection system. In simple terms, it is the balance between the amount of air and fuel entering the combustion chamber for combustion.

B

Bearings are notched (Vòng bi hỏng, vỡ) refers to ball or roller bearings that have developed flat spots or wear marks, which can often be felt when rotating them by hand. These damaged areas indicate that the bearings are no longer running smoothly.

Brake pads & shoes (Má phanh) are the friction components in the braking system. Disc brakes use brake pads, while drum brakes use brake shoes.

Brake squeal (Phanh kêu) is a high-pitched noise produced when braking. Some motorcycle models are more prone to this sound due to pad material or wear conditions.

Brights (Đèn pha) refers to the high beam setting of the motorcycle headlight, used for better visibility in low-light or dark conditions.

Brushes (Chổi than) are carbon components in the electrical system that maintain contact with the commutator to conduct electricity, commonly found in starter motors or alternators.

Bump start (Đẩy nổ) is a method of starting a motorcycle when the battery is dead. It involves turning on the ignition, placing the bike in gear, releasing the clutch while pushing or rolling the bike forward, and then engaging the clutch to start the engine. This technique can be hard on the drivetrain and clutch but is useful in emergencies when no external help is available.

Bungee Cord (Dây chun) is an elastic strap used to secure luggage or items to a motorcycle during travel.

Burning rubber (Đốt lốp) refers to accelerating quickly from a standstill and spinning the rear wheel, often causing the tire to lose traction and produce smoke.

C

Carb (Chế hòa khí / Bình xăng con) is short for carburetor, the component that mixes fuel and air in older motorcycles before the mixture enters the engine.

CDI unit (Con IC) is the ignition control module that manages spark timing in the engine’s ignition system.

Center stand (Chân chống đứng) is the stand that supports the motorcycle in an upright, vertical position when parked.

Choke (Le gió) is a device used to help start a cold engine by temporarily enriching the air-fuel mixture with more fuel.

Choke / enrichment circuit (Cần kéo le gió) refers to the carburetor mechanism used to enrich the fuel mixture during cold starts.

Corrosion (Ăn mòn) is the gradual destruction or deterioration of metal caused by oxidation or rust.

Counterbalance (Đối trọng) is a weight used to balance or counteract another moving part in the engine to reduce vibration.

Crankshaft (Trục khuỷu / Biên) is the main rotating shaft of the engine to which the piston connecting rods are attached, converting linear piston motion into rotational motion.

D

Damper, or Dampener (Bộ giảm xóc) is a hydraulic or friction-based component designed to reduce vibration and oscillation in the suspension or other moving parts of the motorcycle.

Diode, or diode board (Đi ốt một chiều) is an electrical component that allows current to flow in only one direction. It is commonly used in the rectifier and alternator system to convert AC current into DC current for the motorcycle’s electrical system.

Dipstick (Que thăm dầu) is a long, thin metal rod inserted into the engine’s oil reservoir (sump) to check the oil level and condition.

OHC (Trục cam đôi trên đầu bò) is the acronym for Overhead Camshaft. In a dual overhead cam (DOHC) configuration, two camshafts are positioned above the cylinder head to operate the intake and exhaust valves separately. This design improves airflow, allows more precise valve timing, and supports higher engine performance and RPM.

E

Engine casing (Bưởng máy) is the outer housing that encloses and protects all internal components of the engine, keeping the parts sealed, supported, and properly aligned.

F

Faulty ground (Mất chân mát) refers to a poor or broken electrical ground (earth) connection, which can cause electrical issues or intermittent faults in the motorcycle.

Feathering the brake (Bóp phanh nhẹ nhàng) means gently and gradually applying the brake to maintain smooth and controlled deceleration.

Feathering the clutch (Nhả côn từ từ) refers to slowly and smoothly engaging the clutch to ensure a controlled and steady start or gear transition.

Footpegs (Để chân) are the small platforms where the rider and passenger place their feet while riding. Passenger footpegs are often foldable when not in use.

Forks (Giảm xóc trước) are the front suspension components that hold the front wheel, allow steering movement, and absorb shocks from the road.

Four (4)-Stroke (Động cơ 4 thì) is an engine type that completes a power cycle in four piston movements (intake, compression, combustion, and exhaust).

G

Gasket (gioăng) is a sealing component made from paper, rubber, or cork that is placed between two metal parts to prevent leaks of oil, air, or other fluids.

Gearbox, transmission, tranny, box (Hộp số) refers to the system of gears that transmits power from the engine to the rear wheel and allows the rider to change speed and torque.

Gear lash (Độ rơ bánh răng) is the small amount of play or clearance between two meshing gears.

Ground (Dây mát) is the return path in an electrical circuit, often referred to as “earth” in British terminology.

Grounding the plugs (Thử đánh lửa chân bugi) is a diagnostic method where the spark plug is removed and placed against the engine to check for visible spark during ignition testing.

H

Handgrip (Tay nắm) is the rubber covering on the handlebars that provides comfort and better control for the rider’s hands.

Headlight bucket, or shell (Giá đèn) is the metal or plastic housing that holds and protects the headlamp assembly.

Head (Đầu bò) refers to the upper part of the engine mounted on top of the cylinder. It houses components such as the spark plug and valves.

Heavy floats (Sục xăng) refers to carburetor floats that have absorbed fuel and become heavier than normal, causing improper fuel regulation and flooding issues.

Hub (Moay ơ) is the central part of a wheel where the spokes or rim connect, allowing the wheel to rotate around the axle.

I

Idle mixture (Chỉnh ga răng ti) refers to the air-fuel mixture at low engine speed when the motorcycle is idling.

Idle stops (Ốc chỉnh ga răng ti) is the adjustment mechanism on the carburetor that controls the idle speed, preventing the engine from stalling.

Ignition leads (Dây mô-bin / dây cao áp) are the high-tension wires that connect the ignition coil to the spark plug, carrying the electrical charge needed for ignition.

Intermittent shorts (Điện chập chờn / lúc có lúc không) are electrical faults that occur inconsistently, making them difficult to detect and diagnose due to their unpredictable nature.

J

Jet needle (Kim ga) is a component inside the carburetor that helps regulate the amount of fuel passing through the jet, controlling fuel delivery during mid-throttle operation.

Jump starting (Câu ắc quy) is the process of starting a motorcycle with a depleted battery by connecting it to a fully charged battery using jumper cables. This requires proper handling and basic electrical knowledge to ensure safety and avoid damage. It is an important procedure to understand when riding long distances or traveling in remote areas.

K

Kick start (Cần khởi động) is a manual starting mechanism used on older motorcycles, where the rider uses a lever to “kick” and turn the engine over to start it. Before electric starters became common, this was the standard method of starting motorcycles.

Knock (Gõ biên) refers to a knocking or rattling noise from the engine, typically caused by wear or looseness in internal components such as connecting rods. It is an undesirable sound that often indicates serious internal engine damage and may require costly repairs to the lower engine end.

L

Lash (Khoảng trống / khe hở) refers to mechanical play or looseness between components, commonly used when describing valve clearance in engine adjustment.

Lean (Thiếu xăng) describes an air-fuel mixture that contains too little fuel relative to air, which can cause overheating or poor engine performance.

Leaded/unleaded petrol (Xăng có chì / không chì) refers to types of gasoline, where leaded fuel contains lead additives and unleaded fuel does not. Unleaded petrol is the standard fuel used in most modern motorcycles.

The lower end (Bụng máy) refers to the bottom section of the engine, including components such as the crankshaft, connecting rods, and bearings.

Lube, grease (Mỡ bôi trơn) refers to lubricating substances used to reduce friction and wear between moving mechanical parts.

M

Main Bearing (Bi cơ) is a large bearing that supports and stabilizes the crankshaft, allowing it to rotate smoothly within the engine.

Main Bearing Journal (Ca bi cơ) refers to the section of the engine casing where the main bearing is seated and secured, providing support for the crankshaft assembly.

Mudguard (Chắn bùn) is a protective shield located over or behind the wheels, designed to prevent mud, water, and debris from being thrown onto the vehicle or other road users. It is also known as a splash guard.

Muffler (Ống xả / Pô) is a component of the exhaust system that reduces engine noise by controlling and dampening exhaust sound as gases exit the engine.

O

OHC (Trục cam đơn trên đầu bò) is the acronym for Overhead Camshaft. In this design, the camshaft is located above the cylinder head rather than in the lower engine. This reduces reciprocating mass and allows the engine to operate at higher RPMs more efficiently.

Oil filter (Lọc dầu) is a component that removes contaminants and impurities from engine oil, transmission oil, or hydraulic oil, helping to maintain engine cleanliness and longevity.

Oil pump (Bơm dầu) is a key part of the lubrication system that circulates pressurized engine oil to various moving components, ensuring proper lubrication and reducing wear.

P

Petrol, gasoline, or gas, Benzine (Xăng) refers to the fuel used in internal combustion engines.

Pinging, Pinking (Kích nổ sớm) is the premature ignition of the air-fuel mixture in the combustion chamber. It typically produces a light metallic rattling or “tinkling” sound and can cause damage to the piston if not addressed.

Piston slap (Quả hơi gõ) is a knocking noise caused by excessive clearance between the piston and cylinder wall, especially when the engine is cold. It often decreases as the engine warms up and the piston expands, but in severe cases it may persist.

Plugs fouled (Muội bugi) occurs when incomplete combustion causes carbon deposits to build up on the spark plug, which can weaken or block the ignition spark and lead to engine misfiring. The plug must be cleaned or replaced, and the underlying cause should be corrected.

Popping the clutch (Ép côn) refers to quickly releasing the clutch to achieve a rapid start, often resulting in a sudden burst of power to the rear wheel.

R

Renovation (Đại tu) refers to a motorcycle that has been mechanically and/or cosmetically renewed. It is often improved beyond its original condition, although it is sometimes incorrectly referred to as a full “restoration.”

Resistance (Điện trở) is an electrical property that opposes the flow of current and is measured in ohms.

Rectifier (Xạc) is a device that converts alternating current (AC) into direct current (DC), typically used in the charging system of a motorcycle.

Relay (Rơ le) is an electromagnetic switch that uses a small electrical signal to control a larger current in another circuit, enabling remote or automatic control of electrical components.

Rich (Ăn xăng / thừa xăng) describes an air-fuel mixture that contains more fuel than the optimal ratio, which can lead to inefficient combustion and higher fuel consumption.

Ring(s) (Séc măng) are piston rings that seal the combustion chamber, preventing gas leakage and controlling oil consumption. Worn rings can cause the engine to burn oil.

Rocker arm (Cò mổ) is a lever in the valve train that transfers motion from the camshaft to open and close the engine valves.

S

Setting timing (Chỉnh tầm nổ) is the adjustment of ignition timing so that the spark occurs at the optimal point in the engine’s cycle for efficient combustion. This is a critical tuning process for engine performance.

Short circuit (Chập mạch) refers to an electrical fault where a live wire accidentally touches ground or another part of the circuit, often causing failure or damage to the electrical system.

Silicone (Silicon / keo silicon) is a rubber-like sealing material commonly used for repairs and sealing joints in motorcycles and engines.

Piston caliper (Tổng phanh) is the hydraulic component in a disc brake system that holds the brake pads and uses pistons to press them against the brake disc, creating friction to slow or stop the motorcycle.

Spoke tension (Độ căng nan hoa) refers to how tightly the wheel spokes are adjusted using the nipple, affecting wheel strength and balance.

Sprocket (Nhông) is a toothed wheel that engages with a chain to transfer power from the engine to the rear wheel.

Standing on brakes (Phanh gấp) describes heavy or emergency braking, where maximum braking force is applied in a sudden stop.

Starter dragging (Trượt đề) refers to a condition where the electric starter motor struggles due to internal wear or resistance, resulting in weak or slow engine cranking.

Stoppie, stoppy (Bốc đuôi) is a braking maneuver where strong front braking lifts the rear wheel off the ground, balancing the motorcycle on the front wheel.

Stripped threads (Chờn ren) are damaged screw or bolt threads that no longer properly grip, making fastening unreliable or impossible.

T

Tachometer (Đồng hồ tua máy) is a gauge that measures the rotational speed of the engine’s crankshaft, typically displayed in revolutions per minute (RPM).

Tank (Bình xăng) refers to the fuel tank that stores petrol or gasoline for the motorcycle.

Throttle return (Dây hồi ga) is the mechanism that ensures the throttle automatically returns to the idle position when released.

Tire direction (Hướng lắp lốp) indicates the correct mounting direction of a motorcycle tire, marked by an arrow on the sidewall to ensure proper rotation and performance.

Top-end (Đầu máy) refers to the upper section of the engine, including the cylinder, piston, and cylinder head.

Torque (Mô-men xoắn) is a measure of rotational force, such as the force used to tighten a bolt or the twisting power produced by an engine.

Trickle charging (Sạc chậm) is a slow, low-current method of charging a battery to maintain full charge without overcharging.

Triple tree (Vai phuộc trước / chảng ba) is part of the front fork assembly that holds the fork tubes and connects them to the motorcycle frame, allowing steering control.

V

Valve clearance (Khe hở su páp), also called valve adjustment or valve lash, is the gap between the valve stem and the rocker arm. Proper clearance is essential for correct engine performance and longevity.

Valve tuliping (Su páp mòn) refers to a failure condition where the valve head becomes deformed or weakened, often leading to eventual breakage. If it fails completely, it can cause severe damage to the cylinder head and piston.

Viscosity (Độ nhớt của dầu) is the measure of an oil’s thickness or resistance to flow. The correct viscosity must be used depending on temperature and operating conditions to ensure proper engine lubrication.

Wet clutch (Ly hợp ướt) is a type of clutch that operates while submerged in engine oil, helping with cooling and smoother engagement.

Wheelie (Bốc đầu) is a riding maneuver where the front wheel lifts off the ground due to strong acceleration or throttle control.

Wires are fried (Dây điện bị cháy / chập) means the wiring harness has been overheated or short-circuited, damaging the insulation and often requiring replacement.

Wiring harness (Bộ dây điện) is the organized bundle of electrical wires in a motorcycle, usually wrapped in protective covering, that connects all electrical components in the system.

If you have any additional terminology to suggest, please feel free to contact us. Your input can help our customers enjoy a safer and better motorbiking experience in Vietnam.

Many thanks for your support.

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