Yamaha SXV70MK, Owner'S Manual

Page: 57 / 88

8-5
Spark plugs are produced in several different thread
lengths. The thread length or 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 result. Also, if the
reach is too short, carbon will form on the exposed
threads resulting in combustion chamber hot spots and
thread damage. Always use a spark plug with the speci-
fied reach.
Before installing any spark plug, measure the electrode
gap with a wire thickness gauge and adjust to specifica-
tion.
When installing the spark plug, always clean the gasket
surface. Wipe off any grime from the threads and tighten
the spark plug to the specified torque.
ESU03700
Engine idle speed adjustment
CAUTION:
@
●
Be sure to have a Yamaha dealer make this
adjustment.
●
Make sure that the throttle lever moves smoothly.
●
Make sure that the carburetor is synchronized
first.
@
1. Start the engine and warm it up.
NOTE:
@
Refer to the “Starting the engine” section.
@
2. Turn the throttle stop screw
1
in or out to adjust the
engine idle speed.
Spark plug reach
a
: 19.0 mm (0.75 in)
Spark plug gap
b
: 0.7–0.8 mm (0.028–0.031 in)
Spark plug tightening torque:
20 Nm (2.0 m·kgf, 14 ft·lb)
Standard engine idle speed: 1,800
±
100 r/min
E_8ek.book Page 5 Tuesday, June 22, 2004 1:35 PM