Head unit: camshafts

4.3 -

2	Vertical rubber cap

Seal

4	Roller spacer

Bearing

6	Horizontal rubber cap

Screw

8	Valve cover

9	Valve cover gasket

10	Vertical head

11	Horizontal head

Stud bolt

Circlip

Key

16	Vertical head camshaft

22	Horizontal head camshaft

23	Copper gasket

Screw

25	Intake valve cover

Circlip

Spacer

28	Aluminium gasket

Ring nut

O-ring

31	Sensor mount

Sensor

Nut

34	Intake duct

O-ring

36	Rubber cap

Peg

Spare parts catalogue


Head : timing
Vertical head
Horizontal head
Inlet dict

Caution

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.

Removing the engine oil temperature sensor


Operations	Reference See Section
Disconnect oil temperature sensor from main wiring harness	P 1, Arrangement of wiring on frame

Note

This operation can be carried out even if engine is on the frame. For precision purposes, the figures show the head removed from the engine.

The engine oil temperature sensor (32) is placed on the intake valve cover (25) of the horizontal head (11).

Remove the rubber cap (36) and take the sensor (32) off its mount (31).

Unscrew the ring nut (29) from the cover (25).

Remove the circlip (26) from the ring nut and withdraw the sensor mount (31).

Refitting the engine oil temperature sensor

Check seal (28) and spacer (27). Replace as required.

Note

Change the O-rings (30) before refitting.

Installation is a reversal of the removal procedure.


Operations	Reference See Section
Reconnect oil temperature sensor to main wiring harness	P 1, Arrangement of wiring on frame

Disassembling the intake manifold


Operations	Reference See Section
Remove the throttle body	L 6, Removing the throttle body

Note

This operation can be carried out even if engine is on the frame. For precision purposes, the figures show the head removed from the engine.

Undo and remove the lock nuts (33) of the vertical and horizontal head intake manifolds from the stud bolts (12) and (13).

Remove manifolds (34) with O-ring (35).

Unscrew the stud bolts (12) and (13) from the heads, if needed.

Refitting the intake manifolds

Smear some recommended threadlocker on stud bolts (12) and (13), install them to heads (10) and (11) and tighten to the specified torque (Sect . C 3, Engine torque settings).

Check the O-ring (35) and replace it if worn.

Smear O-rings (35) with engine oil, position the intake manifolds (34) and secure them with nuts (33).

Tighten the nuts (33) to the specified torque (Sect. C 3)


Operations	Reference See Section
Fit the throttle body	L 6, Refitting the throttle body

Removing the cam covers


Operations	Reference See Section
Remove the airbox	L 7, Removing the airbox
Remove the battery mount	P 2, Battery mount
Remove the timing covers and the timing belts	N 4.2, Removing the timing side covers
Remove the timing belt rollers from the heads	N 4.2, Disassembling the timing system

Note

For precision purposes, the figures show the head removed from the engine.

Unscrew the retaining screws (1) then remove rubber cap (2) and (6) from heads (10) and (11).

Note

Be careful not to displace the keys (15) in the camshafts (16) and (22) when removing the belt rollers.

Unscrew the retaining screws (21) of the cover (20) supporting camshaft (16) and (22).

Take off the cam cover (20) and its gasket (17).

Disassembling the cam cover

Remove the circlip (18) that holds the bearing in place. Remove the camshaft bearing (19) from the cam cover using a suitable puller.

Caution

Do not reuse the bearings after removal.

Reassembling the cam cover

Install the bearing (19) with the shielded side (A) outward.

Lubricate all components with engine oil before refitting.

Insert the circlip (18) into the cam cover groove to hold the bearing securely in place.

Check gasket (17) and replace if needed.

Removing the valve covers

To remove the cover on the exhaust side (8) of vertical head (10), loosen screws (7) and collect the gasket (9).

To remove the cover on the intake side (8) of vertical head (10), loosen pegs (37) and collect the gasket (9).

To remove the cover on the exhaust side (8) of horizontal head (11) and the cover on intake side (25) of horizontal head (11), loosen screws (7) and collect the gaskets (9).

Refitting the valve covers

Check valve cover gaskets (9) for wear and replace if needed.

Position the valve covers (8) and (25) with the gaskets (9) to the heads.

Note

The cover on intake side (8) of vertical head (10) is secured with pegs (37), while exhaust cover is secured with screws (7).

Tighten pins (37) and screws (7) to the specified torque (Sect. C 3, Engine torque settings).

Removing the camshafts


Operations	Reference See Section
Remove the timing belt rollers	N 4.2, Disassembling the timing system

Note

This operation is also possible with stud bolts fitted onto cylinder head. For your convenience, the pictures show a cylinder head with removed stud bolts.

Remove the cam covers as described above.

Remove the key (15) from the camshaft.

Caution

Rotate the camshaft (16) until finding a position at which cams will not contact the rocker arms. This will avoid damage to the components during removal.

Extract the vertical head camshaft (16) from its seat.

Remove the spacer (4) from the seal (3).

Remove the seal (3) from the head.

Remove the circlip (14) using suitable tweezers.

Use a drift to remove the bearing (5) supporting the camshaft (16).

Check bearing (5) and circlip (14) for wear and replace as required.

Warning

When the bearing is removed, it shall be renewed.

Checking the camshafts

Check that the contact surfaces of the cams are free from scratches, grooves, steps and waving. Worn cams prevent correct timing and lead to loss of performance.

Insert the camshaft between two centres and check deviation using a dial gauge.

- Service limit:

0,1 mm

Note

Actual deviation is half the gauge reading.

The camshaft is marked as follows:

O: horizontal

V: vertical

Checking the oil seals

Change oil seals at each cylinder head overhaul.

Install new seals using suitable tools.

Lubricate oil seal lip after installation.

This operation requires the utmost care.

Checking the circlips

Note

Replace any snap rings which are distorted or have lost their spring.

All circlips have a side (A) which is completely flat and has a sharp edge and a side (B) with a slightly rounded edge.

Checking the bearings

Before a dimensional check, inspect bearing for wear. Do this manually with the bearing installed.

Turn the inner ring in both directions: it should run smoothly and quiet, without jamming.

Push the inner ring outwards at different positions to check for play.

Remove any bearings which run hard or are noisy or have play.

Note

Change the bearings at each cylinder head overhaul.

Refitting the camshaft

Push the camshaft bearing (5) fully home against head wall (10) using a suitable drift.

Fit the circlip (14) in its groove.

Install seal (3) as shown.

Insert the spacer (4) into the seal (3) and push it until it contacts the bearing (5).

Note

Ensure that spacer (4) faces the seal so as not to damage it.

Caution

If you have left the rocker arms in place in the head (Sect. N 4.4, Head unit: valves - rocker arms), rotate the camshaft (16) until finding the position at which the cams will not contact the rocker arms.

Before fitting the camshaft in the head, check shaft punching (A):

O: horizontal

V: vertical

Please refer to "Checking the camshafts".

Insert the camshaft (16) from the left side of the head (10). Push camshaft through spacer (4) until it becomes seated into the bearing (5).

Check key (15) and keyway for wear and then fit it.

Refitting the cam covers

Note

Check gasket (17) and replace if worn.

Position the complete cam cover (20) with the gasket (17) to the left side of head.

Secure the cam cover (20) using the screws (21).

Tighten the screws (21) to the specified torque (Sect. C 3, Engine torque settings).

Note

Pay attention to the key (15) in the camshaft (16).

Position the horizontal head cover (2) to the left side of head and insert the retaining screws (1).

Tighten the screws (1) to the specified torque (Sect. C 3, Engine torque settings).

Repeat procedure for the other head.


Operations	Reference See Section
Refit the timing belt rollers to the heads	N 4.2, Reassembling the timing system
Refit the timing belts and timing belt covers	N 4.2, Refitting the timing side covers
Refit the battery mount	P 2, Battery mount
Refit the airbox	L 7, Refitting the airbox