Generic Race 50, Service Manual

Page: 29 / 209

28
Y N Y N
N Y
Y N
Y N
Trouble diagnosis program for poor engine idle speed
Engine idle speed is
poor
Engine idle speed
too high
Engine idle
speed disabled
Engine idle speed
unstable
Check compression
pressure of cylinder
Pull carburetor throttle valve
by hand to check if it has been
completely closed
Use an ignition timing
light to detect if engine
ignition timing is correct
Compression pressure
of cylinder insufficient
Compression pressure
of cylinder normal
1. Check all joints
outside engine for
air leak
2.
5. Check for the
piston ring broken
or locked in groove
or having
insufficient elastic
force
6. Check piston ring
and cylinder for
wear
Readjust idle speed of
carburetor
Check for
oversize
idling jet
Check if cable
wire of throttle
control cable
can be pulled
to move
smartly in
cable jacket
and if throttle
valve spring is
too soft
Chec
k for
under
size
clear
ance
betw
een
spark
plug
electr
odes
1. Check CDI
igniter for
malfunction
2. Check magneto
flywheel and
trigger coil for
looseness
Engine idle
speed is
enabled after
adjustment
Engine idle
speed is still
disabled after
adjustment
Air adjust
screw on
carburetor or
adjusting screw
on throttle
valve adjusted
improperly
Check idling jet, fuel
way and air way on
carburetor for clogging
Clean and
dredge
Check carburetor float for height
excess
Adjust float
height to
standard value
1. Check insulating body on carburetor for
cracks
2. Check connecting and fixing nut on
carburetor for looseness
3. Check negative pressure pipe of fuel cock
for breakage
4. Check leaf valve for air leak
Adjust
clearance
between
electrodes
Check mixture
ratio of
combustible
mixture