SOHC and DOHC are abbreviations for Single Overhead Camshaft and Double Overhead Camshaft, respectively. These terms refer to the configuration of the camshafts in an engine and how they operate the valves.
In an SOHC engine, there is only one camshaft located in the cylinder head, above the valves. This camshaft is responsible for opening and closing the intake and exhaust valves via a system of rocker arms or cam followers. The camshaft in an SOHC engine is connected to the crankshaft by a timing belt or chain.
In a DOHC engine, there are two camshafts located in the cylinder head, one for the intake valves and one for the exhaust valves. Each camshaft directly operates its corresponding valves without the need for additional components like rocker arms. The camshafts in a DOHC engine are also connected to the crankshaft by a timing belt or chain.
The main advantage of a DOHC engine over an SOHC engine is that it allows for greater control over valve timing and lift. With separate camshafts for intake and exhaust valves, DOHC engines can achieve higher engine speeds and produce more power. They also tend to have better fuel efficiency and emissions performance due to the improved control over valve timing.
They require additional components, such as extra camshafts and associated drive systems, which adds to the overall cost and complexity. SOHC engines, on the other hand, are simpler and lighter, making them more suitable for smaller motorcycles or applications where cost and weight are important factors.
In summary, DOHC engines offer improved performance and control over valve timing, while SOHC engines are simpler and more cost-effective. The choice between the two depends on the specific requirements of the motorcycle, including factors such as power output, weight, cost, and intended use.