Honda Motorcycle Service Manual page 140

CYLINDER HEAD
As the camshaft turns and pushes on the rocker arm
slipper, the rocker arm pushes the tappet plunger
down and oil pressure in the tappet high pressure
chamber increases causing the check valve to close.
During the short time it takes the check valve to close,
a small amount of oil leaksout ofthe chambercausing
the tappet to compress.
As the can1 lobe continues to push o n the rocker arm,
oil pressure i n the high pressure chamber increases
rapidly (because the check valve is closed).
CHECK VALVE
nears maximum lift, oil pressure i n the high pressure
chamber becomes high enough to cause a very small
amount of oil to leakout ofthe high pressurechamber
between the plunger and body.
This allows the plunger to absorb the shock from the
effects of the cam lobe reaching maximum lift.
The high oil pressure keeps the tappet from com-
pressing any furtherwhich then allows the rocker arm
After the cam lobe passes maximum hft, the engine
valve springs force the engine valve to close.
HIGH PRESSURE CHAMBER
I
~ D R A U L I C
TAPPET
to pivot and open the engine valve. As the cam lobe
zg<e>3,When the valve closes completely, the plunger is
, , , " ,
. ? * &
pushed up by the spring i n the high pressure cham-
ber. Oil pressure decreases and as a result the check
valve opens and allows oil to re-enter the high pres-
sure chamber from the reservoir.
All of the above actions keep valve clearance at zero
under all normal operating conditions.
RESERVOIR
PLUNGER
I
A
)
PRESSURE
:HECK VALVE (BALL) CHAMBER
Date of Issue: March, 1995
9-6
o
HONDA MOTOR CO..LTD.