A camshaft is a critical component in a motorcycle engine, playing a pivotal role in controlling the intake and exhaust valves' operation. In this blog, I'll delve into how a camshaft works in a motorcycle engine, sharing insights from my experience as a camshaft supplier.
The Basics of a Camshaft
At its core, a camshaft is a shaft with a series of cams - egg - shaped lobes - attached to it. These cams are precisely designed and positioned along the shaft. The camshaft is driven by the engine's crankshaft, usually through a chain, belt, or gears. The ratio of the camshaft's rotation to the crankshaft's rotation is typically 1:2 in a four - stroke engine. This means that for every two revolutions of the crankshaft, the camshaft makes one full revolution.
Four - Stroke Engine Cycle and Camshaft Function
A motorcycle engine, like most internal combustion engines, operates on a four - stroke cycle: intake, compression, power, and exhaust. The camshaft is responsible for opening and closing the intake and exhaust valves at the right time during this cycle.
Intake Stroke
During the intake stroke, the piston moves downward in the cylinder, creating a vacuum. The camshaft's intake cam lobe pushes against the intake valve's lifter or rocker arm, causing the intake valve to open. This allows a mixture of air and fuel to enter the combustion chamber. The shape and profile of the intake cam lobe determine how long the valve stays open and how far it opens. A well - designed intake cam can optimize the amount of air - fuel mixture entering the cylinder, which directly affects the engine's power and efficiency. For example, a cam with a longer duration (the time the valve is open) and higher lift (how far the valve opens) can increase the engine's power at high RPMs but may sacrifice low - end torque.
Compression Stroke
Once the intake valve closes, the piston moves upward, compressing the air - fuel mixture. The camshaft keeps both the intake and exhaust valves closed during this stroke to ensure that the compressed mixture remains in the combustion chamber. Proper valve closure is crucial for achieving high compression ratios, which improve engine efficiency and power output.
Power Stroke
When the piston reaches the top of the compression stroke, the spark plug ignites the compressed air - fuel mixture. The expanding gases force the piston downward, generating power. Throughout this stroke, the valves remain closed to contain the high - pressure gases and maximize the force applied to the piston.
Exhaust Stroke
As the piston reaches the bottom of the power stroke, the exhaust cam lobe on the camshaft pushes against the exhaust valve's lifter or rocker arm, opening the exhaust valve. The piston then moves upward, pushing the burned gases out of the cylinder through the open exhaust valve. Similar to the intake cam, the exhaust cam's profile affects the engine's performance. A well - designed exhaust cam can improve scavenging, the process of removing the exhaust gases from the cylinder, which in turn allows more fresh air - fuel mixture to enter during the next intake stroke.
Types of Camshafts in Motorcycle Engines
There are different types of camshafts used in motorcycle engines, each with its own characteristics and applications.
Single Overhead Camshaft (SOHC)
In a SOHC engine, there is one camshaft located in the cylinder head. This camshaft is responsible for operating both the intake and exhaust valves. SOHC engines are relatively simple and cost - effective to manufacture. They are commonly found in entry - level and mid - range motorcycles. For example, many small - displacement commuter motorcycles use SOHC engines because they offer a good balance of performance and affordability.
Double Overhead Camshaft (DOHC)
A DOHC engine has two camshafts in the cylinder head, one for the intake valves and one for the exhaust valves. This design allows for more precise control of the valve timing and lift. DOHC engines can achieve higher RPMs and produce more power compared to SOHC engines. They are often used in high - performance and racing motorcycles. The ability to independently control the intake and exhaust valves enables engineers to optimize the engine's performance across a wide range of operating conditions.
Camshaft Materials and Manufacturing
The materials used to make camshafts are carefully selected to withstand the high - stress environment of the engine. Common materials include forged steel, cast iron, and sometimes even aluminum in high - performance applications. Forged steel camshafts are known for their high strength and durability. They can handle the high loads and stresses generated by the valve train. Cast iron camshafts are more cost - effective and are suitable for many standard motorcycle engines. Aluminum camshafts are lightweight, which can reduce the engine's overall weight and improve its power - to - weight ratio.
The manufacturing process of a camshaft is highly precise. It typically involves forging or casting the raw material, followed by machining operations such as turning, grinding, and milling to achieve the exact shape and dimensions of the cams and the shaft. Heat treatment is also applied to enhance the camshaft's hardness and wear resistance.
Our Camshaft Offerings
As a camshaft supplier, we offer a wide range of camshafts for different motorcycle engines. For example, we have the VG1500050096 Camshaft HOWO Euro - 2 / Shacman WP10 61560050096 / VG1500050096 / VG1500050097, which is designed to meet the specific requirements of certain heavy - duty engines. Our L6000000 - PJTL / 1006016 - 36D Camshaft is another high - quality product that provides excellent performance and reliability. And the 61540050004 Camshaft HOWO Euro2/3 Shacman WP10 is suitable for engines that require precise valve timing control.
Our camshafts are manufactured using the latest technologies and high - quality materials to ensure optimal performance and long service life. We understand the importance of a well - functioning camshaft in a motorcycle engine, and we are committed to providing our customers with the best products.
Contact Us for Procurement
If you are in the market for high - quality camshafts for your motorcycle engines, we invite you to contact us for procurement. Whether you are a motorcycle manufacturer, a repair shop, or an individual enthusiast, we can provide you with the right camshafts to meet your needs. Our team of experts is ready to assist you in selecting the most suitable camshaft for your specific application.
References
- "Motorcycle Engine Technology" by David Vizard.
- "Internal Combustion Engine Fundamentals" by John B. Heywood.
- Various technical documents from motorcycle engine manufacturers.