Zhejiang Qianjiang Motorcycle RKV 200, Service Manual, Page: 24 / 171

24
Symptom: Poor idle speed of engine
Diagnosis procedures
Poor idle speed
Higher idle speed Engine has no idle speed. Unsteady idle speed
Check compression pressure in cylinder
Pull throttle valve of carburetor by hand
and see if it is completely closed.
Use an ignition timing lamp to
check ignition timing of engine
Insufficient compression
pressure in cylinder
compression pressure
in cylinder is normal.
1. Check leakage
at
external
connection parts
of engine; 2.Check
valve timing; 3.
Check
if valve
clearance is too
small; 4. Check
tightness between
valve and valve
seat; 5.Check if
piston
ring is
broken or stuck
inside
the ring
groove or of less
elasticity; 6. Check
wear and tear of
piston ring and
cylinder.
Re-adjust carburetor
idle speed.
Check if jet
of idle is
too big.
Check if
throttle control
cable can pull
flexibly in the
cable
jacket
and if throttle
spring is too
soft
1. Check CDI
ignitor. 2. Check
if magneto
flywheel or
trigger coil
looses.
Engine has idle speed
after adjustment.
Engine still has no
idle speed after
adjustment
Air adjusting screw
of carburetor or
throttle adjusting
screw is improperly
adjusted
.
Check if carburetor idle
jet, idle oil path and air
path are clogged
Clean and dredge. Check if float is too high.
Adjust float to
standard height.
1.Check if carburetor insulator is cracked; 2. Check if
connecting and fixation nut on carburetor looses; 3.
Check if negative pressure hose on fuel switch is
broken; 4. Check if leaf valve leaks air.
Adjust clearance
between electrodes.
Check mixture
ratio of
combustible gas
mixture.
Yes No Yes N0
Yes No
No Yes
Yes No
C
heck
if
clearance
of
sp
ark
plug
is
too small.