Bold reference numbers in this section identify parts not shown in the figures alongside the text, but which can be found in the exploded view diagram.

In the event of excessive wear, replace the connecting rod. The small end bushing must be in good condition and firmly driven into its seat. Check for parallelism error measured at 100 mm from the connecting rod longitudinal axis:

the value must be H-h less than 0.02 mm; otherwise, renew the connecting rod.

The cylinder head diameter must be within the specified values (Sect. 3 - 1.1, Cylinder/Piston).

Now ream out the bushing until the inside diameter (D) is 18.006 to 18.024 mm.

Fillet radius: 1.5 mm.

With the aid of a micrometer, measure the ovality and taper of the big-end journals, taking the measurements in various different directions (Sect. 3 - 1.1, Cylinder/Piston).

Use a dial gauge to measure the alignment of the main journals by setting the crankshaft between two opposing centres
(Sect. 3 - 1.1, Cylinder/Piston).

Unscrew all the plugs (4), (3) and (2) from the crankshaft; heating the crankshaft, if necessary, to remove the threadlocker applied at the time of assembly.

Use a hot air gun that can reach 150 °C.

Clean all the oilways using suitable diameter metal brushes and then blow with compressed air to remove any residues that have accumulated and are restricting the oil flow.

Tighten the plugs (2) and (4) to a torque of 13 Nm (Min. 11 Nm - Max. 15 Nm) and the plug (2) to a torque of 15 Nm (Min. 13.5 Nm - Max. 16.5 Nm) (Sect. 3 - 3, Engine torque settings).

To check the assembly clearance between the bearing shells and crankshaft journals you will lay a strip (A) of GREEN “Plastigage PG-1” on the journal.

Fit the connecting rod with the original big-end bearing shells (7) (see procedure on next page) and tighten the screws (8) to a torque of 49 Nm.

If the width measured corresponding to the existing clearance is not within the prescribed limit (Big-end bearing-to-crankpin clearance paragraph under Sect. 3 - 1.1, Cylinder/Piston), either the bearings or the crankshaft must be replaced.

Before starting, check that the crankshaft main bearing journals and big-end journals are free of burrs or evident signs of machining: if necessary, clean the surfaces with very fine emery cloth and oil.

Fit the caps to the corresponding connecting rods. Make sure that the mark on the cap is the on the same side as the mark on the connecting rod.

Use the recommended grease to lubricate the threads and underside of the heads of the new screws (8) and the threaded hole in the connecting rod, packing in grease from both sides of the hole.

The big-end cap screws may only be used for one tightening.

Fit the spacer (H) of the tool 88713.2878 between the connecting rods and take up residual axial clearance with the fork feeler gauge (I) of the tool 88713.2878 which is available in the following thicknesses:

Use the torque wrench, as shown in the picture, to tighten the screws (8) to the torque here below (Sect. 3 - 3, Engine torque settings):

Withdraw the feeler gauge and check that the connecting rod/crankshaft end float is: 0.15 to 0.35 mm.

Install the connecting rod assembly in the crankcase half, carry out the shimming procedure as described in Sect. 9 - 9.2, Shimming the shafts.

Make sure that the connecting rods (5) are correctly positioned in the respective cylinder seats. Incorrect positioning of the connecting rods at this stage will inevitably lead to the need to re-open the crankcase halves.