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.

To disassemble the crankshaft/connecting rods assembly, undo the screws (8) and separate the connecting rod (5) from the crankshaft (1).

In case of excessive wear, renew 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 diameter of the big-end must be within the specified tolerance limits (Sect. C 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 out-of-round and taper of the big-end journals, taking the measurements in various different directions (Sect. C 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. C 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 capable of reaching 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 all the plugs to the specified torque (Sect. C 3, Engine torque settings).

To check the assembly clearance between the bearing shells and crankshaft journals you need to lay a strip (A) of “GREEN Plastigauge 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 bolts (8) to a torque of 49 Nm.

If the width, which corresponds to the existing clearance, is not within the specified tolerance limits (big-end bearing shell-journal clearance indicated in Sect. C 1.1, Cylinder/Piston), it will be necessary to renew either the bearing shells or the crankshaft.

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 bolts (8) and the threaded hole in the connecting rod, packing in grease from both sides of the hole.

The connecting rod screws may be used and tightened once only, after which they must be discarded.

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

0.1 mm - 0.2 mm - 0.3 mm.

Tighten the screws (8) in three stages to the specified torque (Sect. C 3, Engine torque settings), using a torque wrench. Hold the wrench as shown in the photo.

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

Install the connecting rod/crankshaft assembly in the crankcase and follow the shimming procedure as described in Sect. N 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.