7.1 - | Gearbox assembly: gearchange mechanism

1 | Return spring

2 | Washer

3 | Special screw

4 | Gear pawl assembly

5 | Interlock plunger holder

6 | Sealing washer

7 | Detent ball spring

8 | Ball

9 | Circlip

10 | Selector claw return spring

11 | Shim, thickness 0.5

11 | Shim, thickness 0.2

12 | Circlip

13 | Nut

14 | Selector drum control fork

15 | Gearchange lever pin

16 | Shaft with gearchange lever arm

17 | Gearchange lever arm return spring

18 | Screw

19 | Washer

20 | Screw

21 | Washer

22 | Locating ring

23 | Stop plate

24 | Shim, thickness 0.2

24 | Shim, thickness 0.5

25 | Gearchange mechanism

Parts catalogue

Gearchange CONTROL

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 gearchange mechanism

Operation | Section reference
Remove the alternator-side crankcase cover and flywheel/alternator assembly | N 8, Flywheel - alternator
Remove the clutch drum | N 6.3, Removal of the primary drive gears

Undo and remove the gear selector mechanism (25) retaining screws (18) and (20).
Remove screws (18) and (20), washers (19) and (21) and withdraw the gear selector mechnaism complete with the gear lever shaft, spring and stop plate.
Important
Visually inspect the gear selector claw (14) for wear, particularly around the area where it contacts the selector drum.
Disassembly of the gear selector mechanism
If it is necessary to renew any components, disassemble the gearchange mechanism as shown in the exploded view.
Disassembly of the gear interlock plunger and pawl assembly
Unscrew the interlock plunger screw (5) and remove seal (6), spring (7) and detent ball (8).
Unscrew the clutch-side crankcase screw (3) and remove the pawl (4), washer (2) and spring (1).
Refitting the gear interlock plunger and pawl assembly
Fit the pawl (4), washer (2) and spring (1) on the retaining screw (3).
Fit the assembled unit on the clutch-side crankcase half, locating the end of the spring (1) behind the crankcase rib.
Tighten the screw (3) to the specified torque (Sect. C 3, Engine torque settings).
On the special screw (3), fit the gear pawl lever (4), orienting it as shown in the figure, the washer (2) with the square edge side (D) facing the clutch-side crankcase, and the spring (1), positioning it so that the hook end (A) is facing the gear pawl lever. Locate the hook end (A) of the spring on the gear pawl lever as shown in the figure.
Start the screw in the crankcase half. Position end (B) of the spring so that it rests against rib (C) of the crankcase half, as shown in the figure. Tighten the screw (3) to the specified torque (Sect. C 3, Engine torque settings). Check that the spring functions correctly by manually moving the gear pawl lever.
Apply grease and then fit the ball (8), spring (7), and seal (6) into interlock plunger (5) and screw the interlock plunger assembly into the crankcase.
Tighten the gear interlock plunger to the specified torque (Sect. C 3, Engine torque settings).
Reassembly of the gearchange mechanism
If the components of the gearchange mechanism were dismantled on removal, fit the spring (17) on the shaft (16) in the position indicated in the photo. Grease the threaded end of the eccentric gearchange lever pin (15) and install it on the upper part of the gearchange lever, securing it with the nut (13). Screw the nut on by hand (do not tighten).
Insert the shaft (16) in stop plate (23) and washer (24) and secure with circlip (9).
Ensure that the shaft with lever (16) is positioned correctly relative to stop plate (23). The edges of the plate must be equidistant from the pin of the lever; to adjust the position, loosen the locknut (13) and turn eccentric pin (15).
Position the spring (10) between the shaft (16) and the fork (14).
Fit the ring (12) to secure the assembly.
Check that the spring (10) is installed correctly as shown in the figure.
Tighten the nut (13) to the specified torque (Sect. C 3, Engine torque settings).
Refitting the gearchange mechanism
Position the gearchange mechanism (25) in the chain-side crankcase.
Locate the gearbox drum selector claw in the centre of the drum rollers.
Temporarily fit the gearbox lever (or a service lever) and engage third gear.
Fit the plate 88713.1091 in the claw shaft pins (see figure).
Align the notch that marks the centreline of the fork shaft pawl, with the end of the plate.
Then fit the gearchange mechanism retaining screws (18) and (20) with respective washers (19) and (20) and tighten to the specified torque (Sect. C 3, Engine torque settings).
With the gearbox in neutral, check that the lever travel is the same when shifting up and down. The same should apply when a gear is engaged.
Operate the gearchange lever and turn the front sprocket at the same time to check that all the gears engage when shifting up and down.
Remove the gearbox lever.

Operation | Section reference
Refit the clutch drum | N 6.3, Refitting the primary drive gears and checking backlash
Refit the flywheel/alternator assembly. and alternator side crankcase cover | N 8, Refitting the flywheel-alternator assembly