M.26 Part. N. 8000 B0148 (02-2008)
ELECTRIC SYSTEM, DIGITAL INSTRUMENT
Spark plug
Use "NGK" CR8EB spark plug (1) (excluded SMR 450 R) or "NGK" CR9EKB
(SMR 450 R). Check distance "A" (0.6÷0.7 mm / 0.023÷0.027 in. excluded SMR
450 R) or 0.8 mm / 0.031 in. (SMR 450 R) between electrodes. A wider gap may
cause difficulties in starting engine and in overloading coil.A gap that is too narrow
may cause difficulties when accelerating, when idling the engine or when
performing at low speeds. Clean the dirt away from the base of the spark plug
before removing it from the cylinder. It is very useful to examine the state of the
spark plug just after it has been removed from the engine since che deposits on
the plug and the colour of the insulator provide useful indications concerning the
heat rating of the plug, carburation, ignition and general engine condition. Before
refitting the plug, thoroughly clean the insulator using a brass-metal brush. Apply
a little graphite grease to the spark plug thread; fit and screw the spark plug by
hand then tighten to the torque of 10÷12 Nm- 7.4÷8.9 ft/lb. Loosen the spark plug
then tighten it again to the torque of 10÷12 Nm- 7.4÷8.9 ft/lb. Spark plugs which
have cracked insulators or corroded electrodes should be replaced.
1
1
TE
SMR 450 R