Beta RR 400, Operating Instructions Manual

Page: 124 / 392

3
CHECKS AND MAINTENANCE
46
GB
SPARK PLUG
Keeping the spark plug in good condition
makes for reduced consumption and opti-
mum 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.
Note
Black spark plug = mixture is rich
Light brown spark plug = mixture is correct
White spark plug = mixture is lean
This operation must be performed with the
utmost care to avoid severe hand burns.
Always wear protective gloves.
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 com-
pressed 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 specified, 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 im-
mediately replaced.
Conduct the check by referring to the ta-
ble on page 58.
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 NGK DCPR 8 E spark plugs.