Honda UMK431 Owner's Manual page 53

TECHNICAL & CONSUMER INFORMATION
Air cleaner
3,100 +200 rpm
Idle speed
single element, semi-dry
I
FRAME
I
UMK422K1 UMK431 K1
Engine switch
Slide type
I
Throttle control
I
Two motion trigger style
I
Main pipe diameter
solid 0.28 in. (7 mm)
Drive shaft
0.08 in (2.0 mm) 0.06 in (1.5 mm)
Main pipe thickness
1.02 in (26 mm) 0.94 in (24 mm)
Shaft support bushings
3-1 /I 6 inch, 7 spline
2-1/8 inch, 7 spline
Clutch type
4,400 rpm
Clutch engagement
Sealed ball bearings, helical cut gears, no shims required
Gearbox type
1.33
1.31 Gearbox ratio
7
5
Tuneup
ITEM
No other adjustments needed.
Other specifications
See your authorized
Intake: 0.1
2
k
0.02 mm
Valve clearance (cold)
(0.60
-
0.70 mm)
Refer to page: 28
0.024
-
0.028 in
Spark plug gap
MAINTENANCE SPECIFICATION
Exhaust: 0.15 f 0.02 mm
Honda dealer
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