KYMCO Mongoose 50-2T, Service Manual

Page: 54 / 258

3
. INSPECTION/ADJUSTMENT
3-8
VALVE CLEARANCE
(90cc/70cc/50cc-4T)
Disconnect the oil recycle tube at the
cylinder head cover.
Remove the four bolts and cylinder head
cover.
Remove the two screws and two bolts, then
remove the fan cover.
Turn the cooling fan clockwise so that the
“T” mark on the flywheel aligns with the
index mark on the crankcase to bring the
round hole on the camshaft gear facing up
to the top dead center on the compression
stroke.
Inspect and adjust the valve clearance.
Valve Clearance :
90cc: IN: 0.1mm (0.004 in)
EX: 0.1mm (0.004 in)
70cc/50cc-4T: IN: 0.04mm (0.0016 in)
EX: 0.04mm (0.0016 in)
Loosen the lock nut and adjust by turning
the adjusting nut
Special tool:
Tappet adjuster A120E00012
CARBURETOR IDLE SPEED
Warm up the engine before this operation.
Start the engine and connect a tachometer.
Turn the throttle stop screw to obtain the
specified idle speed.
Idle Speed :
90 cc: 1800
±
100rpm
70 cc/50 cc-4T/50 cc-2T: 2000
±
100rpm
When the engine misses or run erratic,
adjust the air screw.
Inspect and adjust valve clearance while
the engine is cold (below 35°C).
＊
•
Check the valve clearance again after
the lock nut is tightened.
＊
Cylinder Head Cover
Bolts
Cooling Fan Cover
Screws
Bolts
Round Hole
Punch Marks
Tappet Adjuster
Throttle Stop Screw
Air Screw
•
The engine must be warm for accurate
idle speed inspection and adjustment.
＊