9.3.1 Crankshaft bushings

Important

• Execute the procedure in Par. 8.2.1 and 8.2.2, before proceeding with assembly.
• The crankshaft  half-bearings are made of special material.
  Therefore, they must be replaced every time they are assembled to prevent seizures.
  
  

1. Fit the new half-bearings A1 onto the crankcase upper half B1 adhering to the reference notches C.
   
   

Importante

• After the half-bearings are fitted, check that the lubrication holes D correspond with the crankcase grooves B1.
• The lower and upper half bearings CANNOT be singularly replaced, and both halves must be replaced together.

2. Fit the new half-bearings A2 onto the lower crankcase B2 using the reference notches C.
3. Lubricate the half-bearings A1 and A2 with oil.

9.3.2 Tappets

1. Lubricate the tappets E with oil.
2. Insert the tappets E into the housings F of the upper crankcase B1.

9.3.3 Oil spray nozzles

1. Insert the sprayers G onto the upper crankcase B1 manually screwing the screw fittings H.
2. Ensure that the spray nozzles G are inserted correctly in their seat, as shown in detail L and tighten the connecting screws H (tightening torque of 10 Nm).

Important

• Carry out the checks described in Par. 8.4.1 and Par. 8.4.2.

1. Check that the crankshaft half-bearings A1 are mounted correctly on the upper crankcase B1.
2. Lubricate the main journal and crankpin J, with oil.
3. Insert the crankshaft M into its seat on the upper crankcase B1.
4. Insert the 2 shoulder half-rings N1, between the crankshaft M and the upper crankcase B1 (Q detail).

9.3.5 Lower semi-crankcase

1. Check that the coupling surfaces P are free from dirt and grit.
2. Spread a bead of Loctite 5660 of approx 1,5 mm thickness on the surface P of the upper crankshaft half B1 being careful not to block the oil feed grooves X and the return oil sump Y.
3. Insert gasket S into the seat of crankcase B1.
   
   

4. Check that the crankshaft half-bearings A2 are mounted correctly on the lower crankcase B2.
5. Assemble the 2 shoulder half-rings N2 onto the lower crankcase B2 applying two drops of grease to keep them in their seat.
6. Join the two crankshaft halves B1 and B2 observing the guide pins T.

Fig 9.7 - Fig 9.8

Fig 9.9

Fig 9.10

Tab 9.2

Important

• The fastening bolts J, K must be replaced every time they are assembled.
• Failure to adhere to the bolt fixing procedures may compromise the functionality of the engine, and also may cause damage to persons and property.
• Tighten capscrews J, K observing the cycles, tightening, and subsequent rotation as indicated in Tab. 9.2.

7. Apply "Molyslip AS COMPOUND 40" on the threads and under the head of capscrews J and K and manually tighten them until their stop.
8. Tightening the screws J, K strictly following the sequence indicated in the Fig. 9.9 or Fig. 9.10 and the tightening torque indicated in the Tab. 9.2.
9. Check that crankshaft M rotates smoothly.
10. Insert gasket W into the seat of crankcase B (ST_47).

Fig 9.11

9.3.6 Camshaft

1. Lubricate the pins S2 the cams S3 of the camshaft S1 all the housing Q1 with oil.
2. Insert the camshaft S1 all the way into its housing Q1.
3. Fit the lock ring S4 on to the crankcase B to hold the position of the camshaft S1.

Fig 9.12

9.3.7 Timing system gear

1. Check that the pin P1 is correctly fitted on the crankshaft M.
2. Position the gear M1 on the crankshaft M respecting the reference with pin P1.
3. Fully tighten the screw N1 interposing tool ST_41 between N1 and M1.
4. Position the gear R1 on the camshaft S1 observing the marks T1 of the gear M1.

Important

• Failure to comply with the marks T1 on the gears M1 and R1 causes engine malfunction and serious damage.
• Fastening capscrew R2 must be replaced every time it is assembled.

5. Assemble gear R1 by means of capscrew R2 (tightening torque 100 Nm).
6. Check that crankshaft M rotates smoothly.

Fig 9.13

Fig 9.14

9.3.8 Piston rings

1. Perform the operations described in Par. 8.5.3.
2. Put the scraper ring Z3 onto the piston Z.
3. Put the 2° seal ring Z2 on the piston Z.
4. Put the 1° seal ring Z1 onto the piston Z.
5. Perform the operations described in Par. 8.5.4.
6. Position the segment openings with a 120° angle between them (Y).

NOTE: do not use the segment opening with the pin hole (N)

7. Lubricate the piston skirt and piston rings with oil.

Fig 9.15

Fig 9.16

9.3.9 Piston

Importante

Fig 9.17

Fig 9.18

9.3.10 Piston and connecting rod assembly

Important

• Before assembling the piston and connecting rod assemblies, execute the controls described in Par. 8.5.5.

1. Rotate the crankshaft M by moving the crankpin J1 to a TDC position of the affected cylinder.

2. Lubricate the piston skirt and rings Z.
3. Check that the half-bearing U1 is mounted correctly and lubricate it thoroughly.
4. Using the piston ring compression pliers, insert the piston inside the cylinder W1 by around 10mm (height T2).
   
   

Important

• Make sure you are at the stage described in Point 1.
• Piston Z must be assembled with notch K1 on the side of the skirt facing oil spray nozzles G.
  
  

5. Rotate the piston Z by 10° counter-clockwise with respect to its correct assembly position (Fig. 9.20 - height T3).
   
   

Fig 9.20


Fig 9.21

Fig 9.22

Fig 9.23

 Important

• Leave the ring compressor assembled on the piston.

6. Push piston Z downwards without introducing the segments in the cylinder, rotate piston Z by 10° in a clockwise direction (value T3 – correct assembly position).

7. Push the piston Z downwards by centering the crankpin J1 with the connecting rod F2.
8. Rotate the crankshaft M by moving the crankpin J1 to a BDC position of the affected cylinder.
9. Push the piston Z downwards by centering the crankpin J1 with the connecting rod F2.
10. Turn the crankcase on support to assemble the con rod capp F1.
11. Check that the half-bearing U1 is mounted correctly on the connecting rod cap F1.
    
    

  Important

• Check that the break levels of connecting rod cap F1 coincide perfectly onto connecting rod F2 before screwing on and tightening capscrews E1.

12. Couple the connecting rod cap F1 to the connecting rod F2 using the marks made at disassembly (Par. 7.12.2 and 7.12.5).
13. Apply "Molyslip AS COMPOUND 40" on the threads and under the head of capscrew E1 and manually tighten them until their stop.

  Important

• Failure to adhere to the assembly procedures may compromise the functionality of the engine, and also cause damage to persons and property.

14. Tighten the screws E1, alternately, strictly following the tightening torques indicated (Tab. 9.3).
15. Repeat the operations from 1 to 14 for each cylinder.
16. Check that the connecting rods have axial play and the crankshaft M rotates smoothly.
    
    

NOTE: After the check carried out at point 16, position the shaft M with the first cylinder to TDC.

Tab 9.3

NOTE: Click by side to play the procedure.