Manual - Chapter 1 Engine

28. Reassembling the engine unit: refitting the crankshaft

  1. Check that all components are completely clean and dry. Ensuring that the correct shells are used, refit the shells to their respective recesses ensuring that the locating tangs (except thrust bearings) engage correctly in their grooves.
  2. Lubricate the crankshaft bearing journals and the bearing shells liberally with clean engine oil.
  3. Lower the crankshaft carefully into place, aligning the timing marks (if possible) on 75 models, and refit the main bearing caps using the marks or notes made on dismantling to ensure that each is refitted the correct way round and on its original bearing. Note particularly that the bearing shell locating grooves are next to each other on the 'lower' side of each bearing.
  4. Tighten the bearing cap retaining bolts evenly and progressively to the specified torque setting. To apply pressure evenly work in the following sequence to tighten the caps (bearings numbered consecutively from front to rear, number 1 being at the front/cam chain end): on 75 models tighten first number 2, followed by numbers 3, 1 and 4 on 100 models tighten first number 3, followed by numbers 2, 4, 1 and 5.
  5. Check after each cap is tightened that the crankshaft is able to rotate freely and with reasonable ease; some stiffness will be inevitable, especially if new shells have been fitted.
  6. On 75 models, if the balancer shaft is now to be refitted, rotate the crankshaft to the position where the timing marks will align, as noted on removal.

28.1a Check correct shells refitted on reassembly - ensure locating tangs engage fully ...

28.3a Oil all bearings surfaces liberally before refitting crankshaft

28.3b Use identifying marks noted or made on removal to replace bearings caps correctly

28.4 Tighten main bearing cap bolts evenly and in correct sequence - see text