1984 Ski-Doo Shop Manual, Page 188Get this manual
SECTION 03 TRANSMISSION SUB-SECTION 02 (DRIVE BELT)
DEFLECTION ADJUSTMENT
Elan model
The proper drive belt deflection is obtained by chaincase movementTo do so, loosen the chaincase retaining "U" clamp and screw or unscrew the chaincase adjusting bolt
Safari, SS-25Sonic models
Drive belt deflection is adjusted with the movement of the chaincasecountershaft assemblyTo do so, loosen the chaincase retaining nut; unlock the countershaft support attachment and screw or unscrew to adjust distance between pulleys