Specifications

r
30
Chapter 1 Engine, clutch and gearbox
1 6.3a Lift out mainshaft and layshaft clusters complete
17.1a Clean cases thoroughly and check bearings etc
17.2 This casing has been damaged by the kickstart
mechanism; it required renewal
1 6.3b Do not lose these shims which may remain in case
•
17.1b Ensure that oilways are kept clear
18 Crankshaft and gearbox main bearings: removal
1 The crankshaft bearings will remain on their shafts when
the crankshaft assembly is withdrawn from the crankcase. A
puller or an extractor will be necessary for their removal as they
are a tight fit on the shafts.
2 The gearbox bearings are a light press fit in the crankcase
castings. They can be drifted out of position, using a mandrel of
the correct size and a hammer.
3 If necessary, warm the crankcases slightly, to aid the
release of the bearings.
19 Examination and renovation: Big-end and main bearings
1 Failure of the big-end bearing is invariably accompanied by
a knock from within the crankcase that progressively becomes
worse. Some vibration will also be experienced. There should be
no vertical play in the big-end bearing after the old oil has been
washed out. If even a small amount of play is evident, the
bearing is due for replacement. Do not run the machine with a
worn big-end bearing, otherwise there is risk of breaking the
connecting rod or crankshaft.