Ignition Timing
Picking the correct time to send a spark to the spark plug is key to getting good power. At low revs, there is more time for the fuel to burn, so the spark can be just a short time before TDC. But at higher revs, the time is much less, so the spark is 'advanced' by up to 40 degrees. For example, Honda's CBR1000RR runs timing of 3.2° BTDC (idle) up to 45° BTDC (at 7,500 rpm).
Valve included angle
The valve included angle is, simply, the angle between the inlet and exhaust valves, as viewed from the side of the bike (on an inline four). A narrower included angle is preferable for a compact, efficient combustion chamber shape and higher compression, but is harder to design. Older engine designs tend to have wider included angles because they had side-draft carburettors that needed long, curved inlet ports. Air cooled engines also have larger included angles so they can channel enough cooling air around the spark plug and combustion chamber.
Valve open duration
The period of crank rotation where a valve is opened. Note: this isn't a time - the amount of time the valve is open will vary according to engine speed. It's given in degrees, so if an inlet valve opens at 25° BTDC and closes at 65° ABDC, the duration will be 180° (25+65+90).
Valve timing
The point at which the inlet and exhaust valves are opened (and closed) is a vital part of how an engine makes its power. Generally speaking, at higher engine speeds there's less time for the engine to suck in the fuel/air mixture and push the burned exhaust gasses out, so it needs to keep the valves open as long as possible. But if they're opened too early or closed too late the engine can lose power. Since the timing of the camshafts is normally fixed on bikes, the point at which the valves open and close is a matter of compromise (many cars have variable valve timing, but Kawasaki's Concours 1400 is the only current bike so equipped).
Valve timing is measured in degrees at the end of the crankshaft. Imagine the crank has a wheel on the end with a mark for the conrod, and degrees marked round its edge. Opening points are measured in degrees After Top Dead Center (ATDC) for inlets and Before Bottom Dead Center (BBDC) for exhaust valves. So if an inlet valve timing is 30° BTDC then the inlet valves are lifted off their seats when the crankshaft is 30° before the 12 o'clock position - or five minutes to 12. If it closes 30° After Bottom Dead Center, the valve is back on its seat when the crank is at the 25 minutes to 12 position.
Similarly, an exhaust valve might open at 60° BBDC, and close at 30° ATDC.
Valve overlap
At high engine speeds, the inlet charge of the fuel/air mixture is moving quite quickly, so its momentum keeps it going. Clever design can use this momentum to improve performance by leaving the inlet valves open even after the piston has started moving back up. The momentum of the inlet charge keeps pushing the air in, squeezing more mixture into the cylinder and improving torque and power.
Similarly, at the start of the cycle, the earlier the inlet valve opens the sooner it can get the inlet charge moving. But the exhaust valve may still be open, allowing the maximum amount of burnt gasses out. This 'overlap' works well at high revs, but may cause poor low-speed running and uneven idle, since the gasses aren't properly controlled. High performance race cam designs often have a lot of overlap, which explains their impact on normal road riding use.
Valve lift
How far the valve is opened by the cam nose. It's generally measured at the middle of the opening period. More lift allows more of the fuel/air mixture in for a given opening duration, improving performance. But increase lift too much and the valves might start hitting the piston - which will kill your engine in a hurry.