1970-1979 Ski-Doo Snowmobiles Service Manual, Page 53Get this manual
46 Belt Disintegration Flex Crack Between Cogs
CHAPTER THREE
Belt disintegration as illustrated in Figure 15 is the result of excessive belt speed caused by using an improper drive belt or oil on pulley surfacesIncorrect gear ratio may also cause belt disintegrationRefer malfunction to dealer for his analysisEdge Cord Breakage
Cracks appearing between belt cogs (Figure 17) generally indicate that the belt has lost its flexibility and must be replacedSheared Drive Cogs
The type of edge cord breakage shown in Figure 16 is usually caused by pulley misalignmentRefer to Chapter Seven for applicable pulley alignment procedure