Yamaha RHINO YXR66FSEW Owner's Manual page 218

0–10 hours:
Avoid continuous operation above half throttle. Al-
low a cooling off period of five to ten minutes after
every hour of operation. Vary the speed of the ve-
hicle from time to time. Do not operate it at one set
throttle position.
10–20 hours:
Avoid prolonged operation above 3/4 throttle. Rev
the vehicle freely but do not use full throttle at any
time.
After break-in:
The vehicle can now be operated normally.
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