ENGINE
DESCRIPTION
B
The
Inclined engine is
of
unit
construction,
having
three
cylinders, a 120
degree
crankshaft, and
three
aluminium alloy mating
crankcase
sections. The
transmission housing
Is
an
Integral
part
of
the
centre
crankcase, and
the
clutch
and
primary
cransmlsslon
are housed
In
separate cases,
bolted
on
to
the
main
crankcase sections.
The
aluminium alloy
cylinder
head has cast-In
Austenitic valve
seat
Inserts, and
houses
the
over~
head valves, which
are
operated
by
rocker
..
rms
housed
In
detachable alloy
rocker
boxes. Six
aluminium push rods
operate
the
rocker
arms,whlch
are
each fitted
with
adjusters,
accessible
when
the
rocker box covers are removed.
The
aluminium alloy die cast pistons each have
two
compression rings and
one
all
scraper
ring. The
connecting rods
are
of
H
Section
RR56 alloy,
with
detachable end
caps.'
These
Incorporate
steel
backed renewable
"shell"
type
bearings.
Each
of
the
connecting
rod
caps
Is
machined from a steel
starnping and held
In
position
by
means
of
two
high
tensile steel bolts, which
are
tightened
to
a pre-
determined extension figure, to give the correct
working clearance
for
the
bearing
on
the
crankshaft
Journals.
The
Inlet and
exhaust
camshafts
are
fitted trans-
versely
In
the
upper
part
of
the
crankcase, and are
driven
by
a train
of
timing
gears
from
the
right side
of
the
crankshaft.
One
end
of
the
exhaust
camshaft
drives
the
adjustable
contact
breaker
which
Is
fitted with
an
automatic
advance and
retard
mechanism, and
the
opposite
end drives
the
tachometer
cable.
The
three-throw
one piece crankshaft
Is
supported
by
two "shell" type be.rlngs, a roller
be.rlng.t
the
right Side, and a
b.1I
bearing at
the
left side. The
two
plain Inner
main
bearings are
each
retained
by
an
alloy
cap
held
by
studs
and self locking nuts.
which are tightened
to
a
predetermined
torque
setting.
The big-end be.rlngs and
the
two
Inner main
bearings are lubricated
under
pressure
by
all which
flows through drlllings
In
the
crankcase and crank-
shaft, from
the
double
gear
all pump.
all
pressure
In
the
lubrication system
Is
governed
by
means
of
a relief valve, which
Is
situated
at
the
rear
of
the
engine behind the Inner primary chalncase cover.
The aluminium alloy cylinder barrel
Is
fitted with
Austenitic Iron liners, and houses
the
pressed-In
aluminium alloy
tappet
gUide blocks. Power from
the
engine
Is
transmitted
through
the
engine
sprocket
and primary chain
to
the
shock absorber
unit, diaphragm clutch, and five speed constant
mesh transmission. Primary chain adjustment
Is
given
by
a plvotted
rubber
lined tensloner, which
Is
Immersed
In
the
primary chain all bath.
The electrical
generator
set
consists
ofa
rotor
which
Is
fltted
to
the
right end
of
the
crankshaft and a six
call
stator
which
Is
mounted on
three
pillar bolts
Inside
the
timing cover. A
starter
motor
and
solenoid are mounted on
the
crankcase behind
the
cylinder block,
the
motor
pinion engaging with a
gear ring pressed on
to
the
clutch body.
Carburatlon
Is
by
three
Amal
type
626
concentric
carburetters with a
common
linkage.
63
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