Yamaha RD400 - Page 87

1. Spark plug reach 1. Portee de bougie
2. Spark plug gap 2. Ecartement des electrodes
1. Zündkerzen-Gewindelänge
2. Zündkerzen-Elektrodenabstand
and erode. Consult your dealer before chang-
ing to a different type of spark plug.
Standard spark plug:
NGK B-8ES
Spark plugs are produced in several different
thread lengths. The thread length (reach) is
the distance from the spark plug gasket seat
to the end of the threaded portion. If the
reach is too long, overheating and engine
damage may result. If the reach is too short,
spark plug fouling and poor Performance may
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