1978 Polaris RXL Service Manual, Page 60Get this manual

1978 Polaris RXL Service Manual, Page 60

FORMULA TO CALCULATE MPH
To calculate the exact MPH of your snowmobile, many factors have to be known hese

factors are listed as follo ws:

Maximu RPMrefer to engine specification sheet
Percent of jackshaft speed or ratio between drive and driven clutchesRXL RXL .99 :1 7150
Root diameter of front sprocketsGear ratiore fer to gearing specificationsFormu la
RPM of jackshaft speedspeed of top gea rRoot diaof sprocket TT (3 .1416)

:::; ftper revolution3
Speed top gear (answer No1) gea ratio