Bold reference numbers in this section identify parts shown in this exploded view diagram. These parts do not appear in the figures near the text.

Change a connecting rod when badly worn. Connecting rod small end bush must be in good condition and firmly set in its seat. Measure parallelism error 100 mm away from the longitudinal axis of the connecting rod:

H less h must be lower than 0.02 mm. If not so, change the connecting rod.

Big end diameter must be within the specified limits (Sect. C 1.1, Cylinder / piston).

Connecting rod big end bearings must be within the specified wear limits (Sect. C 1.1, Cylinder / piston).

Replace small end bush (6) using the tool shown in the figure. This tool lets you extract the worn bush and install a new bush (A) at the same time.

Locate the new bush to the small end of the connecting rod with the opening at right angles to the upper hole of the con-rod small end.

Bore out bush until obtaining a bore diameter (D) of 18.006-18.024 mm.

Fillet radius: 1.5 mm.

Use a micrometer to measure oval and taper of the crank pin. Measure oval and taper in several different directions (Sect. C 1.1, Cylinder / piston).

Use a dial gauge to measure the alignment of main bearings with the crankshaft placed between two centres (Sect. C 1.1, Cylinder / piston).

Use an air gun capable of reaching 150°C.

Clean all lubrication ducts with suitably sized metal brushes and blow with compressed air to remove any deposits preventing proper oil circulation.

Tighten all plugs to the specified torque (Sect. C 3, Engine torque settings).

Fit the connecting rod with the original bearings (7) following the procedure at next page. Tighten the bolts (8) to 49 Nm.

Replace the bearings or the crankshaft if the thickness measured (the clearance) is not within the specified limits (see Section C 1.1, Cylinder / piston, for con-rod bearings to crankpin clearance).

Before reassembly, check that main bearings and crank pins are free from burrs and fretting: use fine emery cloth and oil, if necessary.

Fill the recommended grease into the two ends of the hole to lubricate threads and underside of the new bolts (8) and the thread of the shaft.

Fit the fork gauge part no. 88765.1000 (available shims are 0.1 mm, 0.2 mm and 0.3 mm thick) between the connecting rods and take up residual end float. Tighten the bolts to the specified torque with a torque wrench in three steps (Sect. C 3, Engine torque settings). Hold the wrench as shown in the photograph.

Remove the feeler gauge and ensure that axial play between connecting rods and crankshaft is 0.15 - 0.35 mm.

Install the complete connecting rod unit inside casing, proceed to shimming as described in Sect. N 9.2, Casing unit: crankcases.

Make sure that the connecting rods (5) are correctly positioned in the cylinders. Incorrect positioning will inevitably lead to reopening of the casing.