6-23
EBU00209
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 op-
eration under load does not harm the engine.
Each full throttle acceleration sequence should be
followed with a substantial rest period for the en-
gine by cruising at lower r/min so the engine can
rid itself of the temporary build up of heat.
If any abnormality is noticed during this period,
consult a Yamaha dealer.
U5NF61.book Page 23 Wednesday, June 13, 2001 5:18 PM
8-33
CAUTION:_ Never operate the engine with the air filter ele-
ment removed. This will allow unfiltered air to
enter, causing rapid engine wear and possible
engine damage. Additionally, operation with-
out the air filter element will affect carburetor
jetting with subsequent poor performance and
possible engine overheating. _
EBU00296
Carburetor adjustment
The carburetor is a vital part of the engine and re-
quires very sophisticated adjustment. Most adjust-
ing should be left to a Yamaha dealer who has the
professional knowledge and experience to do so.
However, the idling speed may be performed by
the owner as a part of the usual maintenance rou-
tine.CAUTION:
The carburetor was set at the Yamaha factory
after many tests. If the settings are disturbed
by someone without sufficient technical
knowledge, poor engine performance and
damage may result.
U5NF61.book Page 33 Wednesday, June 13, 2001 5:18 PM
