Manual - Chapter 3 Gearbox

2. Removing the gearbox from the frame

Note: It is possible to remove the engine and transmission as a single unit from the frame, and then to separate the unit into its major components. If this course is preferred, refer to Chapter 1- Engine for details of the procedure. Given below are instructions on removing the transmission from the frame, leaving the clutch and engine in place.

  1. If the gearbox is to be overhauled, drain the oil ( see Minor Service - Oil change).
  2. Lift the seat and remove both side panels, then disconnect the fuel injection control unit and withdraw it with the storage tray. See Chapter 5 - Fuel & Oil.
  3. Remove the battery as described in Major Service - Battery check, then secure the coolant expansion tank to the frame seat tube out of harm's way. Remove their retaining screws and withdraw the ignition HT coil and alternator covers.
  4. Remove the exhaust, as described in Chapter 5 - Fuel & Oil.
  5. On K75, K75 C and K75 T models unscrew the adjusting nut to disconnect the rear brake operating rod. On all models, disconnect the wires from the speedometer impulse transmitter, the stop lamp rear switch and the gear position indicator switch.
  6. Remove the rear wheel. See Chapter 9 - Wheels & Brakes. Remove its four mounting nuts and withdraw the rear mudguard.
  7. Working as described in Chapter 8 - Final drive, remove both footrest plates and the rear brake system components, disconnect the rear suspension unit bottom mounting and withdraw the final drive case, dismantle the swinging arm and withdraw the final drive shaft.
  8. Disconnect the clutch cable from the release lever and remove it from the gearbox. See Major Service - Adjust Clutch. Working as described in Chapter 2, remove the clutch release mechanism components.
  9. Unscrew the starter motor mounting bolts and withdraw the starter motor. Enlist the aid of two assistants for the next stage.
  10. Place a jack under the engine, with a block of wood positioned to protect the sump fins and raise the machine until the centre stand is clear of the ground; be very careful that the machine does not topple. Place blocks of wood or similar supports underneath the sump and in front of the front wheel. If a suitable support can be obtained, the frame rear end should be secured at the necessary height. If work is being carried out in a building with strong enough roof timbers a satisfactory support could be obtained by hanging the frame rear end from one of these timbers using a length of strong rope or a strong webbing strap. If all else fails have your assistants support the frame rear end while the gearbox is removed.
  11. When the machine is securely supported, unscrew the four mounting bolts and withdraw the stand assembly. Unscrew the six gearbox/bellhousing Allen screws.
  12. Remove the two gearbox/frame mounting Allen bolts and pull the gearbox backwards off the clutch splines. There should be no difficulty in separating the gearbox from the engine, but if any problems are encountered first check that the starter motor and all the gearbox/ bellhousing retaining screws have been removed, also any ether component which might prevent separation. If the gearbox is still stuck in place it is probably because one of the locating dowels is corroded. Apply a good quantity of penetrating fluid to the affected area, allow time for it to work, then tap the gearbox backwards with a few firm blows of a soft-faced mallet on the swinging arm pivot or frame mounting lugs.
  13. Note the two large locating dowels protruding from the mating surface of the bellhousing rear face; it is essential that these are present and firmly fixed at all times to ensure that the gearbox is correctly aligned on the bellhousing. If this is not the case, the clutch action will be heavy and the clutch will suffer excessive spline wear and even serious damage. Note also the rubber fillet sealing the clutch housing, underneath the starter motor; check that this is securely installed.
  14. On 75 models, and on 100 models if necessary, withdraw the clutch pushrod from the input shaft.


Next Section: 3. Gearbox: dismantling

2.11a Remove the stand assembly.....

2.11b permit the removal of all gearbox/bellhousing retaining screws