SPARK PLUG
To avoid burns, put on
protective gloves before
performing the operation.
Keeping the spark plug in good condi-
tion makes for reduced consumption and
optimum engine performance.
It is advisable to remove the spark plug
when the engine is hot (and naturally off)
because the carbon formation and the
colour of the insulator provide important
information on carburetion, lubrication,
and the general condition of the engine.
If the insulator appears white, the mixture
is probably too lean; conversely, a green
insulator denotes a rich mixture. The
mixture is correct when the insulator is
tan coloured.
To carry out the check, simply remove the
current cap and then unscrew the spark
plug using the spanner provided.
Carefully clean the electrodes using a
wire brush. Blow the spark plug with
compressed air to prevent any residues
from getting into the engine.
Measure the spark gap with a thickness
gauge. The gap should be 0.6-0.7 mm.
If the gap is not as specifi ed, restore
the proper gap by bending the earth
electrode.
Check that the insulator is not cracked
and that the electrodes are not corroded,
in which case the spark plug should be
immediately replaced.
Conduct the check by referring to the ta
ble on page 63.
Note:
Lubricate the spark plug thread, and
then (when the engine is cold) screw in
the spark plug by hand to its abutting
end. Finally tighten the spark plug with
the spanner.
Note:
• Always use spark plugs:
URBAN 200 = NGK DR8 EA
URBAN 125 = NGK CR7 HSA
55
3
GB