K-CYCLE
ROTARY
OHC
over head cams can be single or double shafts per cylinder head, they can operate straight on top of the valve buckets with spacing pads or the play in the valves can be closed by a hydrolic system controlled by the oil pump.
OHC can also controll rockers which push directly on the valves.
DOHC ment more valves in a smaller combustion chamber which resulted in more power, the earlier models of DOHC ran on 2 seperate gears but now one of the gears is run off the other by a scissor drive, this means that money is saved on manufacturing because it is that much more narrow.
compared to push rod OHC
-is more expensive because of the seperate head.
-more efficient because ther is no air pressure lost down the pushrod guide itself.
-harder to time with belt and chains because some push rod engines are run of gears.
-in an OHC there are more working parts than on a pushrod engine e.g. long timing chains/belts, hydrolic tentioners and oil feeders to the cams themselves.
A side valve system is essentuly a pushrod engine minus rockers with the valves directly on the end of the rod. - more jurasic park style
