Motobecane 40 - Page 87

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POOR
ENGINE
PERFORMANCE
Very
often
poor
engine
performance
may not
be
related to
the engine itself,
but
to one or
several
frequently
unsuspected
secondary
causes
In
such a case, w€ suggest
the following:
L. Check that the decompressor
control
is
not or has
not been overadjusted
which
might damage
the valve and enta'il
compression
loss
(tfris
is
a
fre-
quent
cause).
2.
Check that the throttle slide opens
ful1y.
Quite
often the control
is
badly adjusted
and the
engine is
starved even at
full throttle
position.
3. Check that there is no brakinq
action
due to
chains
beinq
too tiqht.
In
this
respectr
oh
Mobylettes fitted
with
a
swing arm
rear suspension, ten-
sion
adjustment must be
performed
in
the runninq
position,
the
machine
loaded
wjth a rider weighing
about 165
'l
bs.
4. Check
variator
operation.
5. Make sure
the
bel
t
i s
comect'ly al
i
gned.
6. Make
sure the
brakes
are
not adjusted
too
tightly.
7. Check that the
fuel
cap vent
hole is
not
clogged
as
this may
bring about
poor
fuel
supply.
B. Check that the
spark
plug
is in accordance
with the manufacturer's
speci-
fi
cati ons.
9. Check that the
exhaust is neither
partially
blocked
nor
blocked. If
thjs is the
case, clean
out the complete
exhaust
system.
10. Very important
note:
Quite
often
poor
engine
performance
may
be
caused
by overt'ightening the
cyljnder
head
nuts
and
thereby
distorting
the cylin-
der.
(Cylinder
head nut
torque
is
9 lbs.
ft.)
LIGHTING
CIRCUIT
LIGHTS AT ALL
Faulty
zener
diode
*(6V)
Faulty headlamp switch
Faulty
lighting coil
or coil
ground
Magneto harness burnt or
grounding
behind engine
Wiring
harness
connector
block disconnecteQ
behind carburetor
Improper wire
connections
Bl own
bul bs
i
I. NO
A)
B)
c)
D)
E)
F)
c)
R0 83