Cylinder Compression Test; Cylinder Head Cover Removal - Honda 2003 NPS50 Ruckus Service Manual

CYLINDER HEAD/VALVES
CYLI NDER COMPRESSION TEST
Warm up the engine to normal operating tempera­
ture.
Stop the engine and remove the spark plug cap and
spark plug (page 4-6).
Connect a compression gauge to the spark plug
hole.
7
T o avoid discharging Open the throttle all the way and crank the engine
the battery. do not with the kick starter or electric starter u ntil the
operate the starter gauge reading stops rising.
motor for more The maximum reading is usually reached within 4 -
seconds. 7 seconds when using electric starter.
than
COMPRESSION PRESSURE:
1,393 kPa (14.2 kg/em', 202 psi) at 1 ,500 rpm
Low compression can be caused by:
- Blown cylinder head gasket
- Improper valve adjustment
- Valve leakage
- Worn piston ring or cylinder
High compression can be caused by:
- Carbon deposits in the combustion chamber or
on piston head
CYLI NDER HEAD COVER REMOVAL
Remove the fuel tank (page 6-28).
Disconnect the engine breather and air supply
hoses.
Remove the bolts and cylinder head cover.
Remove the 0-rings from the cylinder head cover.
9-6
0-RINGS