Briggs & Stratton 750 DOV Series Spécifications télécharger pdf (Page 67)

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11

Remove Piston and Connecting Rod

1. Carefully remove any carbon or ridge at

top of cylinder bore (A, Figure 11-1) to

prevent ring breakage.

2. Remove rod bolts (B) and connecting rod

cap (C).

3. Push piston (D) and connecting rod (E) out

through top of bore.

Disassemble

1. Using pliers, rotate piston pin clip (F) until

one end is exposed in notch in pin bore

(G), then remove clip.

2. Slide out piston pin (H) and remove

connecting rod from piston.

3. Using Piston Ring Expander #19340,

remove the compression ring (J) and the

wiper ring (K).

NOTE: Identify the top side of each ring before

removal.

4. The oil control rings (L) consist of two thin

steel rails and a spring expander. These

must be removed by hand as follows:

• Grasp one end of the upper steel rail and

wind the rail from the oil ring groove into

the center ring groove. Repeat into top

ring groove and then off the piston.

• Remove the spring expander then

remove the lower steel rail.

Inspect

Check Piston and Pin

1. Inspect piston for scoring, galling, or other

damage. Replace piston if necessary.

2. Using a dial caliper or plug gauge,

measure the pin bore diameter in the

piston. Compare with reject dimensions

listed in Section 12 - Engine

Specifications. If pin bore meets or

exceeds reject dimension, replace the

piston.

3. Measure outside diameter of pin and

compare to the reject dimensions listed in

Section 12 - Engine Specifications. If pin

meets or exceeds the reject dimension,

replace the pin.

4. Clean any carbon from the top ring groove

in piston. Place NEW ring in groove and,

using a feeler gauge, measure the

clearance between ring and ring land

(Figure 11-2).

5. Repeat procedure for wiper ring groove

and oil control ring groove.

6. Compare with reject dimensions listed in

Section 12 - Engine Specifications. If

clearance meets or exceeds the reject

dimensions, replace the piston.

Figure 11 - 2

Check Connecting Rod

If either the crankpin bearing or the piston pin

bearing is scored or discolored, the rod must be

replaced.

1. Reinstall rod cap and bolts on rod. Tighten

bolts until snug.

2. Using a dial caliper or plug gauge,

measure the two bearing diameters.

Compare with reject dimensions listed in

Section 12 - Engine Specifications. If

either bearing meets or exceeds its reject

dimension, the rod must be replaced.

3. Remove rod bolts and rod cap. Set aside.

Check Ring End Gap

It is recommended that the entire ring set be

replaced when servicing the piston and/or

cylinder bore. However, the original rings can be

re-used if they are not damaged and are

checked as follows:

1 2 ... 62 63 64 65 66 67 68 69 70 71 72 ... 77 78

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