Yamaha 2003 yz85, Owner'S Service Manual

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T U N
SETTING
Jet needle groove position adjustment
Should the engine be hard to run smoothly at
intermediate speeds, the jet needle
1
must be
adjusted. If the mixture is too rich or too lean at
intermediate speed operation, irregular engine
operation and poor acceleration will result.
Whether or not the richness of the mixture is
proper is hard to be determined by means of
the spark plug and therefore, it should be
judged from your feeling of actual engine oper-
ation.
1. Too rich at intermediate speeds
Rough engine operation is felt and the
engine will not pick up speed smoothly.
In this case, step up the jet needle clip by
one groove and move down the needle to
lean out the mixture.
2. Too lean at intermediate speeds
The engine breathes hard and will not pick
up speed quickly.
In this case, step down the jet needle clip
by one groove and move up the needle to
enrich the mixture.
Standard clip position No.2 groove
5PA70090