Engine Assembly; Preparing The Crankcase; Central Main Bearings - Kohler KD 425-2 Workshop Manual

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KD 425-2 Workshop Manual_cod. ED0053029360_1° ed_ rev. 00
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Notice: These instructions are valid for engines up-dated
prior to the publication of this manual. Any modifications
must be checked on the technical circulars.
Before assembling the engine carefully clean all parts and
dry them with compressed air. Lubricate moving parts to
prevent seizing when starting up. Replace the gaskets with
new ones each time the engine is assembled.
Use torque wrenches to ensure that the correct tightening
torques are applied.

Preparing the crankcase

Clean the mating surfaces of sealing compound residues or other fo-
reign material using a copper scraper or fine emery stone. Make sure
that the oil passages are open and free of built-up deposits.
1. Fit the plugs (A, fig.55) in their holes.
2. Insert the internal accelerator lever (B, fig.55) into the crankcase
with its spring taking care to protect the oil seal O-ring from da-
mage.
Complete the external assembly with plate, spring, lever, etc. as
shown in figure 55.
3. Mount the bearing bush (gear train side) using either a standard
press or a made-to-measure punch as shown in figure 56. F i t
the bush by matching the hole with the passage on the crankca-
se. Bushes with standard or smaller internal diameters can be or-
dered as required.
4. Insert the complete oil pressure relief valve (A, fig. 57) into its
housing (C, fig.57). Make sure that the valve ball seat is free of
dirt that could reduce the effectiveness of the pressure seal.
Secure the oil pressure valve with the relative screw (B, fig. 57).
5. Insert the cylinder studs and the centring pins.
A warped oil retainer may allow the introduction of air into
the engine thus causing crankcase ventilation problems.
Use genuine oil retainers.

Central main bearings

Fit the shells into their seats and coat with a thin film of oil.
The reference numbers (fig.58) must be aligned on each half-shell,
making sure that the oil passages match the corresponding openings
in the crankcase. Torque the bearing assembly bolts (fig. 59) to:
kgm 2,2 (Nm 21,6)

ENGINE ASSEMBLY

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