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3. 2
CYLINDER
HEAD
3. 2
Cy
linder Head
A.
Construction
The cylinder
head contains the camshafts,
cam
followers,
torsion bar valve
springs, valves, cam
chain guide rollers,
etc
.,
which are
assembled
on the
main part of the head.
The
main part of
the
head
consists of combustion
chamber,
intake
and
exhaust
system components,
etc
.
On
the
right end of the
exhaust camshaft is mounted
the
tachometer gearbox.
The contact breaker is installed on the
left
end.
The
combustion
chamber
is
semi-spherical in shape
and
incorporating
a squish
area
for better
cooling
and
improved
combustion
efficiency.
(Refer to
Fig. 3.
12l
(SQUA
SH
AREA)
This is the area in which part
of
the fuel
mixture between
t
he
piston and cylinder
head is
compressed
further
at the end
of
the
compressio:1
stroke to be iniected into the main mixture, creat-
ing
a
swi
rl.
The
injected
mixture is
directed
at
the spark plug
to increase
the propagation of
combustion.
Even
a lean or a
slow
burning
fuel
mixture will
produce
a
smooth combustion with
a reduced
tendency
toward
engine
"knock".
!Refer to
Fig.
3. 13)
The
DOHC (double
overhead
camshaft)
system
wh
ich
is
provided
with
two independent
camshafts,
has
lightended
the reciprocating
mass of the valve
mechanism, increasing
engine speed
and operating
stability
at high output.
Also,
the
combustion
effi-
ciency
has been greatly
..
improved
,
since
the valves
may
be ideally
positioned and
the
spark plug
located
in
the center
of the
combustion chamber
for greater
efficiency.
The flow
of
cooling air
around the upper portion
of
the
combustion
chamber is
excellent, and together
with
the
good
heat
transfer of
the aluminum alloy
head, the cooling efficiency
has been
increased
notably.
Fig
.
3. 12
(D
Cylinder head
fig
.
3.
13
Squish
area
17
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