4. Final drive: refitting

  1. Before refitting the final drive assembly check the swinging arm gaiter is securely fixed and undamaged (especially if signs of water were noted in the swinging arm). Apply a coat of the specified lubricant (See Minor Maintenance and Major Maintenance) to the drive shaft splines and check that the swinging arm is securely supported at the normal working position.
  2. Especially on early 100 models, but on any model which has been fitted with a new or different final drive housing or swinging arm, measure the depth of the tapped holes in the final drive housing into which are screwed the retaining bolts; they must be at least 17.5 mm (0.7 in) deep, measured from the joint face. The manufacturing limits of the swinging arm mounting flange thickness were increased and to ensure that the thread length remained sufficient the final drive housing holes were drilled and tapped deeper; longer bolts 45 mm instead of 40 mm were also used. The early swinging arm and final drive housing are identified by the external horizontal cast rib which is 3.5 mm (0.14 in) wide; on modified castings it is 10 mm (0.40 in) wide. To ensure that the bolts are long enough to clamp the housing threads securely but without bottoming in their tapped holes select bolts as follows. If a modified final drive housing is fitted to either type of swinging arm, bolts 45 mm long must be used, also if an unmodified final drive housing is fitted to a modified swinging arm; note however that in this latter case the 40 mm bolts must be used if the longer bolts bottom in the tapped holes. Obviously if two unmodified (early type) castings are being installed, the 40 mm bolts are required.
  3. If water was found in the swinging arm apply a thin coat of sealant to the mating surfaces and check that the two locating dowels are securely fixed in the final drive housing surface. Refit the housing, aligning the drive pinion splines with those of the drive shaft rear end, then push the housing firmly into place. Refit and tighten the retaining bolts to the specified torque setting.
  4. Refit the rear suspension unit to its bottom mounting and tighten the mounting nuts and bolts to the specified torque setting. Remove the swinging arm support.
  5. Refit the rear brake components and rear wheel, as described in the relevant Sections of Chapter 9 Wheels &Brakes.
  6. Press the speedometer impulse transmitter into the final drive housing, ensuring that it does not contact the rotor and that the sealing O-ring is coated with the specified oil to prevent any risk of damage. Fasten the retaining screw and secure the transmitter lead in the guide provided.
  7. Where necessary, fill the housing with oil as described in Major Maintenance - Change the final drive case oil, then check the oil level. Make a final check that all disturbed components are correctly refitted and fully secured, that the brake is correctly adjusted and werking properly and that the rear suspension is werking properly. Check also that the rear wheel is free to rotate smoothly and easily before taking the machine out on the road.


4.3a Rotate crownwheel flange to align shaft and drive pinion splines on refitting


4.3b Tighten bolts to specified torque setting