Yamaha TT-R90(T) Owner's Service Manual page 142

IDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
3 - 8
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
Inductive tachometer
G
To spark plug lead.
3. Adjust:
Idle speed
G
Adjustment steps:
Adjust the pilot screw.
G
Refer to "PILOT AIR SCREW ADJUST-
MENT" section.
Turn the throttle stop screw 1 until the
G
engine runs at the lowest possible speed.
To increase idle speed →
Turn the throttle stop screw 1 in a.
To decrease idle speed →
Turn the throttle stop screw 1 out b.
Inductive tachometer:
YU-8036-B/90890-03113
Engine idling speed:
1,400 ~ 1,600 r/min
VALVE CLEARANCE ADJUSTMENT
NOTE:
The valve clearance should be adjusted
G
when the engine is cool to the touch.
The piston must be at Top Dead Center
G
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
Air scoop (right) 1
G
Air filter case 2
G
2. Remove:
Spark plug
G
Tappet cover (intake side) 1
G
Tappet cover (exhaust side) 2
G
3. Remove:
Timing plug 1
G
Crankshaft end cover 2
G
O-rings
G
INSP
ADJ