Manual - Chapter 1 Engine

34. refitting the auxiliary drive shaft components and the bellhousing


  1. Before refitting any of the covers, check that the mating surfaces are free from dirt, oil, grease or old jointing compound and that they are flat and undamaged.
  2. The rubber seals at the crankshaft and cylinder head covers should be checked for damage; they can be re-used many times if they are not torn, stretched, or distorted. Soak a rag in suitable high flash-point solvent and wipe over the sealing surfaces and seals to remove all traces of grease; do not forget the conical seals around the retaining bolts. Apply a very thin smear of jointing compound to the moulded inner edges of the cover seals and use this to stick the seal in place in the cover groove. The only jointing compound required on the actual mating surface is a thin smear at the joint between the crankcase and bell housing or crankcase and cam chain cover (crankshaft cover) and between the cam chain cover and cylinder head (cylinder head cover); the coating should extend approximately 10 mm (0.4 in) on each side of the joint. Fit the cover and hold it in place while the bolts are refitted; do not forget a smear of jointing compound around the bolt seals. Tighten the bolts securely but do not overtighten them or the seals will be distorted; use the specified torque wrench settings, where given, and tighten the bolts in a diagonal sequence working from the centre outwards.

Cam chain (engine front) cover

  1. Apply a thin smear of jointing compound to both mating surfaces, fit the new gaskets noting the two locating dowels set in the top surface and offer up the cover. Pass the oil pressure switch lead through the cover passage and keep it taut as the cover is refitted so that a loop of wire does not become trapped.
  2. Smear grease over the lips of the crankshaft front oil seal and carefully ease the cover into place, ensuring that it fits over the locating dowels and that the seal lips are not damaged as they fit over the ignition rotor. Fit the retaining screws and tighten them evenly to the specified torque wrench setting working from the centre outwards in a diagonal sequence.
  3. Feed the oil pressure switch lead up through the cover passage and secure it with the metal clips. On 75 models only, refit the horn.
  4. Fit the ignition trigger assembly as described in Chapter 6 - Ignition and set the ignition timing as accurately as possible.
  5. Refit the engine 'side' covers as described below.

Crankshaft (engine right-hand) cover

  1. This cover is refitted as described in the general notes above (paragraphs 1 and 2).
  2. Refit the radiator bottom hose and refill the cooling system. See Chapter 4 - Cooling.
  3. Refit the cover panels or fairing components disturbed on dismantling.

Cylinder head (engine left-hand cover)

  1. This cover is refitted as described in the general notes above (paragraphs 1 and 2) but note that the half-moon seals at the camshaft rear ends will require special care to ensure that they are properly seated, and that the coil spring must not be forgotten that is fitted to one of the camshaft bearing caps.
  2. The spring is fitted to provide an earth return from the cylinder head cover (which is otherwise totally insulated, being rubber mounted) so that static charges caused by the spark plugs are dispersed; otherwise the static charges might build up and jump the gap to the crankcase, thus producing a stray spark which might well interfere with the ignition system components. On models with black-painted engine castings, ensure that the paint is scraped away from the inside of the cover so that the spring makes a good metal-to-metal contact.
  3. Refit the oil drain plugs (where fitted), tightening them to the specified torque wrench setting, then refit the spark plug cover. See Routine Maintenance - Spark plugs check.
  4. Refit the fairing components disturbed on dismantling

34.2a Engine cover rubber seals can be re-used if undamaged - check carefully

34.2b Apply smear of sealant to stick seal in cover groove

34.2c Sealant is required only at points mentioned in text

34.2d Hold seal securely in place as cover is refitted

34.2e Tighten bolts securely and evenly - do not overtighten

34.3 Cam chain cover upper gasket fits over two locating dowels (arrowed)

34.5 Ensure oil pressure switch lead is correctly routed on refitting cover

34.11 Half-moon seals require special care on refitting cylinder head cover

34.12 Do not omit coil spring - ignition may be damaged