Yamaha BIG BEAR PROFESSIONAL 400 YFM400FPT Owner's Manual page 371

Model
Noise and vibration level:
Noise level (77/311/EEC)
Vibration on seat (EN1032, ISO5008)
Vibration on handlebar (EN1032, ISO5008)
Engine oil/Transfer gear oil:
Type
Recommended engine oil classification:
YFM400FP/YFM400FW
87.1 dB (A)
Will not exceed 0.5 m/s
Will not exceed 2.5 m/s
-20˚ -10˚ 0˚
5W/30
10W/30
API Service SE, SF, SG type or higher
CAUTION:
In order to prevent clutch slippage (since the en-
gine oil also lubricates the clutch), do not mix any
chemical additives. Do not use oils with a diesel
specification of "CD" or oils of a higher quality
than specified. In addition, do not use oils labeled
"ENERGY CONSERVING II" or higher.
10-2
2
2
20˚ 30˚ 40˚ 50˚C
10˚
10W/40
15W/40
20W/40
20W/50
10