Yamaha RS90NW, Owner'S Manual

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ESU03761
Tool kit
The owner’s tool kit has the tools which are sufficient for
most periodic maintenance and minor repairs. A torque
wrench is also necessary to properly tighten nuts and
bolts.
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Tool kit
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RS90N/RS90NR/RS90M/RS90MS
É
RS90R/RS90GT/RSG90/RSG90GT
CAUTION:
@
Before starting the engine, make sure that the tool
kit is properly seated in its holder and is securely
fastened.
@
NOTE:
@
If you do not have a torque wrench available during a
service operation requiring one, take your snowmobile to
a Yamaha dealer to check the torque settings and adjust
them if necessary.
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ESU03681
Checking the spark plugs
The spark plug is an important engine component and is
easy to inspect. The condition of the spark plug can indi-
cate the condition of the engine. Check the coloration on
the white porcelain insulator around the center electrode.
The ideal coloration at this point is a medium to a light
tan color for a snowmobile that is being ridden normally.
If a spark plug shows a distinctly different color, there
could be something wrong with the engine. For example,
a very white center electrode porcelain color could indi-
cate an intake track air leak or carburetion problem for
that cylinder. Do not attempt to diagnose such problems
yourself. Instead, take the snowmobile to a Yamaha
dealer for inspection and possible repairs. You should
periodically remove and inspect the spark plug because
heat and deposits will cause a spark plug to slowly break
down and erode. Consult a Yamaha dealer before chang-
ing to a different type of spark plug.
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