it is a valve that allows more back pressure at low rpm and less back pressure at high rpm. basically a computer controlled restriction in the exhaust right before the muffler. used in Yamaha r6's since 06? and r1 since 02? not sure on exact dates.
The motor being warm has nothing to do with it. The exup valve adjusts the size of the exaust pipe depending on the throttle position and current preformance of the bike. This creats back flow and increases Hp.
Valve pocketing is when a valve is hammering the valve seat.mostly due to miss adjusted valve spring/wrong valve spring/to strong of a valve spring or valve stem to short.Makes the valve seat deeper.
tricuspid valve,bicuspid valve and pulmonary valve
A valve spring "keeper" or AKA a valve spring "retainer" is used to lock a valve spring to the valve.
# The PCV valve is located in the valve cover # Detach the hose from the valve then unscrew the valve from the valve cover
Spill valve is a overflow valve.
Ileocecal valve
The valve guide is a precise hole in the head that the valve stem slides in. The valve is retained by the retainer and two valve locks.
intake valve is bigger.
the triscuspid valve is the valve in a bathroom sink.
a gate valve is a one way totally open or closed valve, a control valve is a variable valve.
Valve clearance