Manual - Chapter 1 Engine

27. Reassembling the engine unit: refitting bearings and oil seal

Note: The refitting of bearings usually involves the use of heat. Refer to the general instructions at the beginning of Section 13.

  1. To refit the auxiliary drive shaft front bearing a stepped drift must be obtained or fabricated which fits closely inside the bearing rollers (ie of the same diameter as the shaft or 20.5 mm/0.81 in). and has a wider section of the same diameter as the bearing outer race so that the bearing is fully supported as it is driven into place. It must be fitted with the manufacturer's marks or numbers facing outwards, ie to the rear and must be driven in until it is flush with the crankcase, which must be heated to 100 - 120 °C (212 - 248 °F).
  2. To refit the needle roller bearings to the starter clutch gear pinion a drawbolt assembly must be used. This is made up from a thick steel washer which is large enough to fit over the end of the bearing and the pinion, a smaller thick washer which is of the same outside diameter as the bearings (ie approximately 26 mm/1.02 in) so that it will fit closely inside the pinion's bearing bore, and a nut and bolt (of as large a diameter as possible) that will fit inside the washers, the pinion and one bearing.
  3. Place the first bearing against the gear pinion so that it is absolutely square to the housing with the manufacturer's marks or numbers facing outwards. Place the smaller washer against the bearing and the larger washer against the opposite end of the pinion. Pass the bolt through the assembly, refit the nut and tighten it lightly. Check that the bearing is perfectly square to its housing and that the small washer is fully seated against the bearing, then tighten the nut gradually to draw the bearing into place until it is seated at a depth of 0.4 :f: 0.2 mm (0.016 :f: 0.008 in) inside the pinion (measured from the pinion end face to the outside edge of the bearing outer race). Dismantle the drawbolt, check that the bearing rollers are free to rotate smoothly and easily, then lubricate the bearing. Repeat for the remaining bearing.
  4. To refit the auxiliary shaft rear bearing, heat the bellhousing to approximately 100 °C (212 °F) and refit the locating circlip. Place the bearing squarely on its housing and tap it into place against the circlip using a hammer and a tubular drift such as a socket spanner which bears only on the bearing outer race. Install the conical spring washer so that its convex side is outwards (ie its outer edge must rest against the bearing, leaving the inner edge raised away from it). Refit the retainer plate and its retaining screws applying a few drops of Loctite 242 or similar thread-locking compound to the threads of each, tighten the screws evenly and securely, using the specified torque wrench setting, where given. Fit a new oil seal (see below).
  5. The output shaft rear bearing must be heated before it can be tapped into place and the retaining circlip refitted in its groove. The front bearing is refitted during the rebuilding procedure.
  6. The output shaft rear oil seal fitting procedure is described in Section 29.
  7. The auxiliary drive shaft rear seal and the crankshaft front seal are fitted to their respective housings in the same way. Polish away any burrs or raised edges, grease the seal inner lips and outer edge and place the seal on its housing with the manufacturer's marks or letters facing outwards, ie with the seal spring-loaded centre lips towards the fluid being retained. Using a hammer and a tubular drift such as a socket spanner which bears only on the seal hard outer edge, tap the seal into place until it is flush with its surrounding housing; note that in the case of the crankshaft seal, it must be flush with the housing rear, or inside, face.
  8. The oil level sight glass must be refitted, as described above, with great care. It helps to coat the outside of the sight glass with engine oil prior to installation.

27.2 Starter clutch gear pinion bearings must fitted to a precise depth in pinion bore