Yamaha YZ85(S)/LC, Owner'S Service Manual

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T U N
SETTING
Change of the heat range of spark plugs
Judging from the discoloration of spark plugs,
if they are found improper, it can be corrected
by the following two methods; changing carbu-
retor settings and changing the heat range of
spark plug.
●
In principle, it is advisable to first use spark
plugs of standard heat range, and judging
from the discoloration of spark plugs, adjust
carburetor settings.
●
If the calibration No. of the main jet must be
changed by ±30, it is advisable to change the
heat range of spark plugs and newly select
the proper main jet.
NOTE:
●
When checking the discoloration of spark
plugs, be sure to stop the engine immedi-
ately after a run and check.
●
Avoid racing.
●
When changing the heat range of spark
plugs, never attempt to change it more than
±1 rank.
●
When using a spark plug other than stan-
dard, check its heat range against the stan-
dard and check that it is a resistance type.
●
Note that even if the discoloration seems
proper, it may slightly vary with the spark
plug maker and oil in use.
Standard spark plug
BR10EG/NGK
(resistance type)
5PA70110