Yamaha BIG BEAR PROFESSIONAL 400 YFM400FPT, Owner'S Manual

Page: 156 / 398

6-23
EBU02092
Engine break-in
There is never a more important period in the life of
your machine than the period between zero and
20 hours.
For this reason, we ask that you carefully read the
following material. Because the engine is brand
new, you must not put an excessive load on it for
the first several hours of running. During the first
20 hours, the various parts in the engine wear and
polish themselves to the correct operating clear-
ances.
During this period, prolonged full throttle operation
or any condition which might result in excessive
engine heating must be avoided. However, mo-
mentary (2–3 seconds maximum) full throttle oper-
ation under load does not harm the engine. Each
full throttle acceleration sequence should be fol-
lowed with a substantial rest period for the engine
by cruising at lower r/min so the engine can rid it-
self of the temporary build up of heat.
If any abnormality is noticed during this period,
consult a Yamaha dealer.
U1C160.book Page 23 Wednesday, May 12, 2004 4:55 PM