8-17
EBU13020
Idle speed adjustment
NOTE:
_
A diagnostic tachometer must be used for this
procedure.
_
1. Start the engine and warm it up for a few
minutes at approximately 1,000 to
2,000 r/min. Occasionally rev the engine
to 4,000 to 5,000 r/min. The engine is
warm when it quickly responds to the
throttle.
2. Connect the tachometer to the spark plug
lead, and then set the idle to the specified
idling speed by adjusting the throttle stop
screw. Turn the screw in direction
a
to
increase the engine speed, and in direc-
tion
b
to decrease the engine speed.
1. Throttle stop screw
EBU00303
Valve clearance adjustment
The correct valve clearance changes with
use, resulting in improper fuel/air supply or
engine noise. To prevent this, the valve clear-
ance must be adjusted regularly. This adjust-
ment however, should be left to a professional
Yamaha service technician.
Specified idle speed:
1,450–1,550 r/min
U5YT10.book Page 17 Friday, December 12, 2003 2:32 PM