9.3 -
1
2
3
4
5
6
7
8
9
 Spare parts catalogue
Important
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.
Removal of the crankshaft/connecting rods assembly
 
Remove the alternator-side crankcase cover and the alternator assembly
After separating the crankcase halves, withdraw the crankshaft (7) complete with connecting rods (2).
Disassembly of the crankshaft/connecting rods assembly
Unscrew the screws (1) and separate the connecting rods from the crankshaft.
Important
Take care not to mix up components of different connecting rods and maintain the original orientation.
Overhaul of the connecting rods
Make the following dimensional checks on the connecting rods:
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In the event of excessive wear (Sect. C 1.1Cylinder/Piston), 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 connecting rod is supplied in two size classes A and B relative to the big end diameter (Sect. C 1.1Cylinder/Piston) as punch marked on the side of the cap.
It is preferable to use crankshafts and connecting rods of the same size class.
Renewal of the small end bushing
To remove the worn bushing, use a suitable drift and a press.
Drill lubrication holes into the new bushing in correspondence with the existing lubrication holes on the connecting rod small end.
Now ream out the bushing until the inside diameter (D) is 20.035 to 20.045 mm.
Renewal of the connecting rod bearings
It is good practice to renew the bearings (3) each time the engine is overhauled.
Replacement bearings are supplied ready for assembly and they must not be reworked with scrapers or emery cloth.
The bearings may belong to two different size classes, each identified by a specific colour (YELLOW and BLUE).
The bearings are comprised of an external steel ring, the inner face of which is electro-plated with a lead-based compound.
The table shows the appropriate bearings to be fitted according to the size class of the crankshaft and connecting rod.
 
Crankshaft overhaul
The main bearing and big-end journals should not be scored or grooved; the threads, keyways, and slots must be in good condi­tion.
Check for fretting or burrs in the fillet between journal and shoulder.
Fillet radius: 2 mm.
Use a micrometer to measure oval and taper of the crank pin. Measure oval and taper in several different directions.
Use a dial gauge to measure the alignment of the main journals by setting the crankshaft between two opposing centres.
At each overhaul, it is advisable to clean the crankshaft’s internal oilways.
The prescribed values are given in Sect. C 1.1, Cylinder/Piston.
The crankshaft is supplied in two size classes (connecting rod pin) A and B, as punch marked on the side of the crank web on the pinion side.
Unscrew all the plugs (4) and (8) from the crankshaft, heating the crankshaft, if necessary, to remove the threadlocker applied at the time of assembly.
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.
Apply DUCAT liquid gasket to the threads of plugs (4) and (8) and refit them.
Lock the plugs to the specified torque (Sect. C 3, Engine torque settings).
Big-end bearing shell-journal clearance
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 bearings and tighten the screws to a torque of 50 Nm.
Remove the connecting rod and compare the thickness of the Plastigage strip to the scale (B).
If the width measured corresponding to the existing clearance is not within the prescribed limit (Sect. C 1.1, Cylinder/Piston), either the bearings or the crankshaft must be replaced.
Reassembly of the connecting rods
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.
Check that the grooves are in perfect condition with no signs of forcing.
Check that each connecting rod (2) and cap are fitted with their locating pins (D).
Wash the pins and dry them with compressed air.
Clean and lubricate the journals and con-rod bearing shells (3) with engine oil and fit the connecting rods in their original mounting positions.
Fill the recommended grease into the two ends of the hole to lubricate threads and underside of the new screws (1) and the thread of the shaft.
Warning
The grease utilised is an irritant in contact with the skin. Wear protective gloves.
Important
Lubrication of big-end cap screws is essential to obtain the correct coupling and to prevent breakage of the parts.
The big-end cap bolts may only be used and tightened once, after which they must be discarded.
Interpose spacer part no. 88713.2878 between the connecting rods and eliminate any residual end float by inserting the fork feel­er gauges coming with the tool: 0.1-0.2 and 0.3 mm thick.
Tighten the bolts (1) as specified:
lubricate with the recommended grease;
tighten to 35 Nm, pause for 2 seconds and then back off through 360°;
stage 1 tightening to a torque of 20 Nm;
stage 2 tightening to a torque of 35 Nm;
stage 3 tightening through 65°±0.5° with torque check (70 to 103 Nm).
Refitting the crankshaft/connecting rod assembly
Install the connecting rod assembly (7) and (2) in the crankcase half.
Important
Make sure that the connecting rods (2) are correctly positioned in the cylinders. Incorrect positioning of the connecting rods at this stage will inevitably lead to the need to re-open the crankcase half.
 
Carry out the shimming procedure (Sect. N 9.2, Shimming the shafts).
 
 
N