High Altitude Tuning - Yamaha VK540EF Service Manual

ESS00096

HIGH ALTITUDE TUNING

To attain the best performance in high altitude conditions, carefully tune the snowmobile as outlined
below.
Test the main jet
(performance & plug color)
OK
Test the low-speed setting
Not OK
Try high-altitude settings
Not OK
Decide if the problem is with the
pilot jet and adjust accordingly
Not OK
HIGH ALTITUDE TUNING
Not OK
Check to see if the gearing is too high or low
OK
OK
OK
Not OK
Adjust the secondary clutch as
required
2-43
Check STD settings
S
Carburetors
S
Spark plugs
Adjust the main jet size according
to the chart
Adjust the size of the main jet
Re-test
OK Not OK
OK
Check the engagement speed
and shift performance
Not OK
OK
Adjust the primary clutch as
required
Not OK
INSP
ADJ
High altitude
tuning OK
OK
OK