2003-2006 Yamaha Snowmobile RX1 Service Manual, Page 83Get this manual
HIGH ALTITUDE TUNING
INSP ADJ
HIGH ALTITUDE TUNING To attain the best performance in high altitude conditions, carefully tune the snowmobile as outlined belowCheck STD settings Carburetors Spark plugs
Adjust the main jet size according to the chart
Test the main jet (performanceplug color) OK
Adjust the size of the main jet
Re-test OK Not OK
Test the low speed setting OK Adjust the engine idle speed by turning the stop screw of carburetorCheck to see if the gearing is too high or low OK