Yamaha BLASTER YFS200T Owner's Manual page 276

Inspection
The spark plug is an important engine compo-
nent and is easy to inspect. The condition of the
spark plug can indicate the condition of the
engine.
The ideal color on the white insulator around the
center electrode is a medium-to-light tan color
for a ATV that is being ridden normally.
Do not attempt to diagnose such problems your-
self.
Instead, take the ATV to a Yamaha dealer. You
should periodically remove and inspect the
spark plug because heat and deposits will cause
the spark plug to slowly break down and erode.
If electrode erosion becomes excessive, or if
carbon and other deposits are excessive, you
should replace the spark plug with the specified
plug.
Standard spark plug:
BR8ES (NGK)
8-27