Yamaha WR45OFR service manual Pilot jet adjustment, Standard pilot jet #45 #48

SETTING

T U N

Pilot jet adjustment

The richness of the air-fuel mixture with the throttle open 1/4 or less can be set by adjust- ing the pilot jet 1.

Standard pilot jet

#45

*#48

* Except for USA

Effects of adjusting the pilot jet (reference)

Å 1/4 1/2 3/4

#48

#42

ı

+5%

#45

–5%

ÅIdle ı Fully open

Jet needle groove position adjustment

Adjusting the jet needle 1 position affects the acceleration when the throttle is 1/8 to 3/4 open.

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.

Step down the jet needle clip by one groove and move up the needle to enrich the mixture.

Standard clip position

No.4 groove

Effects of changing the jet needle groove position (reference)

Å 1/4 1/2 3/4

1

2

ı

+10%

3

–10%

ÅIdle

ıFully open

1 No.5 groove

2 No.3 groove

3 No.4 groove

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