Yamaha YS928J Owner's Manual page 51

PERIODIC MAINTENANCE
1
1. Spark plug cap
4. Remove the spark plug using a plug
wrench.
5. Check the spark plug for any signs of
burns.
Burn marks on spark plugs are usually
medium-to-light tan. If there are any
black or white burn marks, consult your
Yamaha dealer.
6. Remove deposits (carbon) from the
spark plug electrode using a plug
cleaner or a wire brush.
7. Check the spark plug gap.
Spark plug:
NGK BPR4ES
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
1. Spark plug gap
2. Spark plug number
3. Insulator
8. Install the spark plug.
Tightening torque:
18 Nm (1.8 m·kgf, 13 ft·lbf)
TIP
If a torque wrench is not available when
installing a spark plug, a good estimate of
the correct torque is 1/4–1/2 turn past finger
tight. However, the spark plug should be
tightened to the specified torque as soon as
possible.
1. Fully tighten the spark plug using your fingers.
2. 1/4–1/2 turn
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