Automatic Decompression; Camshaft End Play; Dynamic Balancer (On Request) - Kohler KD225 Workshop Manual

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DISASSEMBLY/REASSEMBLY

Automatic decompression

With the engine at a standstill and up to a rate of about 300 RPM,
spring 1, acting on weights 2 and 3 via lever 4 and pin 5, keeps the
exhaust valve open during the compression phase also.
Once the engine exceeds the 300 RPM rate, weights 1 and 2 keep
pin 5 in the hold position owing to the action of the centrifugal force. In
this position, cam 6 can regularly control the exhaust valve thanks to a
ridge on the pin itself.
Since there is then no compression in the cylinder, the engine will ea-
sily start when the self-winder is used.
69 70

Camshaft end play

Perform this check before fitting cylinder head and tappets including
the injection tappets.
Temporarily fit camshaft 1 complete with washer; tighten gear cover 2
to 25 Nm.
Check end play by moving the camshaft back and forth using a suita-
ble tool; the end play value is 0.10÷0.25 mm and is not adjustable.
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Dynamic balancer (on request)

The dynamic balancer is supported by two identical ball bearings hou-
sed in the crankcase and in the gear cover on the timing side respec-
tively.
1 is the reference point for timing with the cranksaft gear (see below).
Dimensions (mm):
A = 14.983-14.994
B = 14.99-15.00
C = 34.89-35.00
D = 34.958-34.983 (bearing housing diameter on crankcase and gear
cover on timing side).
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KD 225_315_350_400_440 Workshop Manual_cod. ED0053029330_1° ed_ rev. 00