Carburetor Idle Speed Adjustment; Carbon Removing For Exhaust Pipe; Muffle; Cylinder Compression Pressure Test - Sym Fiddle 50 Service Manual

Carburetor Idle Speed Adjustment

Caution
Inspection & adjustment for idle speed have
to be performed after all parts in engine had
been adjusted in specification.
Idle speed check and adjustment have to be
done after engine is being warn up. It
around operates engine from stop to running
for 10 minutes.
Remove the body cover.
Park the scooter with main stand after warned up
engine. According to the required idling and air
screw to adjust to specified idle speed.
Idle speed: 2000±100 rpm

Carbon Removing For Exhaust Pipe

& Muffle
Remove the body cover.
Remove the exhaust pipe & muffler.
Clean the carbon deposits on the muffler &
cylinder exhaust edge.
Cylinder Compression Pressure
Test
Remove the left body cover, and warn up engine.
Stop the engine and remove the spark plug.
Insert the compression gauge and wide open the
throttle, and then rotate the engine by means of
the starting motor.
Compression pressure: 7.0±1 kg/cm
Probable causes for low compression pressure.
Damaged cylinder head gasket.
Worn piston ring
Worn cylinder
Probable causes for high compression pressure.
Carbon on the combustion chamber or cylinder
head
This chapter Contents
2. SERVICE MAINTENANCE INFORMATION
Adjust the idling after warn up engine for 10
minutes.
1. Connect tachometer.
2. Adjust the idle speed screw to let engine
speed in 2000±100 rpm.
3. Insert the sampling pipe of the CO/HC meter
to the test hole on the front end of exhaust
pipe. Adjust the idling emission value to
standard range. (CO: 1.8-2.6%)
4. Slightly accelerate the throttle valve and
release it. Repeat this operation for 1-2
times.
5. Read the engine idle speed and the emission
value after engine speed in stable. Repeat the
operation on step No. 2 – No. 4. until these
value within standard range.
2
Pilot screw
Idle speed adjustment screw
Compression pressure gauge
2-11