1970-1979 Ski-Doo Snowmobiles Service Manual, Page 21Get this manual
14 On machines with pressed steel chaincase and aluminum chaincase (without external tension adjuster) oil level should be flush with indicator level or plug (Figure 8)On models with aluminum chaincase with external tension adjuster, total quantity of oil is oz(l80cc)On later model Blizzards oil level should be to bottom of the oil level opening as shown in Figure 9Top off oil level if necessary with Ski-Doo chaincase oil or equivalent (SAE 30)Use syringe or oil suction device to remove old oil when changing oil for machine storage preparation
CHAPTER TWO
Filler plug
Rotary Valve Oil Reservoir