Valve Clearance - Shineray XY400-2 Maintenance Manual

XY400–2 Maintenance Manual
the crankcase. Insert the tensioner 4 locking key
into the tail end of the new chain tensioner, turn and
retract the front end of the tensioner and lock it, then
replace with a new sealing washer, mount the new
chain tensioner and fasten.
Pull off the tensioner locking key to tension the timing
chain.
Replace with a new sealing washer and screw up the
bolts on the tail end of the chain tensioner.
Notice
When the timing chain is loosened, never turn the
crankshaft for fear of interlocking tooth while
timing.
Old tensioner
Tensioner locking key
5.

Valve clearance

Notice:
While adjusting the valve clearance, the engine shall
be cold.
(Temperature ＜35℃)
Noise will stem from too big valve clearance. However
if there is too small gap or even no gap at all, closing
of the valve will be hindered, which will cause many
problems such as engine stall, power loss, etc.
Therefore, the valve clearance must be checked
periodically.
The valve clearance should be inspected and adjusted
on a cold engine by the following procedures:
Remove the caps of the central hole and the ignition
timing observation hole on the left crankcase cover.
Remove the caps of the two air valves on the cylinder
head.
Upper eyehole cover
Confirm the upper dead point
Turn the nut of the flywheel clockwise until the
engraved "T" mark on the flywheel aligns with the
engraved line on the top of the crankcase cover, and
both intake and exhaust rock arms do not move but
stop at their loosest position, which shows that the
piston is in its top dead center position of the
compressing stroke. If the "T" mark is near its right
position but rock arms will move apparently when
flywheel rotate a small angle, the flywheel is not in the
27
Inspection and adjustment
Eyehole cover