The meaning of DOHC and SOHC

     DOHC is stands for Double Over Head Camshaft (as an alternative to the SOHC engine type). The layout engine uses a two cam (Noken) on top of the engine block. This also means that on V DOHC engine has 4 camshafts because there are two blocks that make up the engine to simplify manufacturer for apply four valves per cylinder. Most DOHC engine also brings propeller engines (RPM) is higher. Location of valves that better optimize the setup that maximizes engine performance as well. But the lack is ; the weight will increase, more expensive, more complicated and have more parts to play two-camshaft. 
-Excess and Deficiency DOHC :
    Excess :
    1. More refined engine sound.
    2. More power due to more complete combustion.
    Deficiency:
    1. Prices become more expensive.
    2. More wasteful of fuel and maintenance should be better than SOHC.

     SOHC is stands for Single Over Heat Camshaft. This technology is a technology where an engine has a regulator valve open and close only one / single. Such systems makes the bike or car has largest power and torque since the early rotation engines until middle engine speed, this makes fuel consumption more efficient. This device is usually applied to bikes or cars that are created to divide the city congestion.
-Excess and Deficiency SOHC :    
    Excess :
    1. Number of components is less.
    2. More fuel efficient, so the cheaper price.
    3. The machine does not heat up quickly because the lubricating oil can go up to the header block.
    4. The fuel can be burned all / efficient combustion systems.
    Deficiency :
    1. Engine noise is more rugged
    2. Power is relatively small so that less responsive
    3. The cost of its service is more expensive
    4. If components are damaged one can spread to the other.