N a typical engine of motorbike [ conventional type ] there is one inlet valve for input of combustion mixture and one exit valve. If there valves are replaced by 4-valves, i.e. 2 inlet valves and two exit valves, intake and exhaust process of the engine can be made better. There 4-valves come out to be smaller and lighter in weight and aid the easy flow of gases. Bajaj Discover 125 ST has a 4-valve DTSi engine. A 4-valve DTSi engine was patented by Bajaj as worlds first of its kind for Pulsar 135 LS. A 4-valve engine has about 50 % increased area available for combustion as compared to conventional 2-valve engines. This facilitates induction of more quantity of charge ( air-fuel mixture) and also evacuation of all burnt gases inside the combustion chamber ensure faster, cleaner & more efficient combustion. The result is increased engine performance-power, throttle response, pick up of all engine speeds. As a consequence a 4-valve engine is lighter, more powerful and efficient. There are no limitations to rpm in an 4-valve engine [ well still one may not cross 11 k rpm mark
