High Altitude Tuning - Yamaha RS90K Manuel D'atelier

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
OK
Not OK
Try high altitude settings
OK
Not OK
Decide if the problem is with the pilot
jet and adjust accordingly
OK
Not OK
HIGH ALTITUDE TUNING
Adjust the main jet size according to the
chart
Adjust the size of the main jet
Not OK
Re-test
Check to see if the gearing is too high
Adjust the engine
or low
idle speed by
turning the stop
screw of carbure-
tor.
Adjust the engine idle speed
by turning the stop screw of
carburetor.
Check the engagement speed and
shift performance
Adjust the primary clutch as
required
Not OK
Adjust the secondary clutch as
required
2-73
Check STD settings
• Carburetors
• Spark plugs
OK
Not OK
OK
Not OK OK
Not OK
INSP
ADJ
High altitude
tuning OK
OK
OK