The specific kind of oil recommended varies according to average operating temperature. So make sure the engine oil is at the specified level.
The Yamaha Warrior YFM350XR(C) owner's manual recommends:
YAMALUBE 4 (20W40) or SAE 20W40 from above 30 degrees F (-1.11 degrees C)
YAMALUBE 4 (10W30) or SAE 10W30 from 10 degrees F up (-12.2222 degrees C), not more than 110 degrees F (43.33 degrees C)
SAE 5W30 from 30 degrees F (-1.11 degrees C) down to below 0 degrees F (-20 degrees C)
Recommended engine oil classification: API Service SE, SF, SG type or higher
Check out the details about the recommended oil on page 10-2 of the owner’s manual.
ATVs and UTVs represent a significant investment for any sportsman. Just like your truck, your home or anything else you spend a big chunk of change on, you want it to last for as long as it can. You need to take care of these items and, on occasion, roll up your sleeves and get to work.
Check out some tips on how to extend the life of your ATV at Gameandfishmag.com.