Yamaha Inticer II, SRX Series, and Exciter Series snowmobiles require 2-stroke oil at a mix ratio of 50:1 of fuel to oil for synthetic oils and 45:1 with mineral/non-synthetic oil.
Important Note: Do not mix mineral-based oil with synthetic-based oil. Do not mix different brands or types of synthetic oil. It is very important to use high-quality synthetic or semi-synthetic oil. Otherwise, you will damage your engine.