The engine unit is so designed that the only parts of it which cannot be removed easily while the
main crankcase/cylinder block casting is in the frame are the auxiliary drive shaft, including the
starter idler shaft and starter clutch, and the output/balancer shaft
assemblies. If the bellhousing or the crankcase lower section are to be removed
to reach any of these components, the gearbox and final drive must be removed
first (see Chapter
3 - Gearbox) so that the clutch can be withdrawn (see
Chapter 2 - Clutch) to give access to the bellhousing. The engine and frame will require
very careful supporting if this procedure is adopted. See Section 7.
All other components can be removed with the main crankcase/cylinder block casting and the
bellhousing still in the frame. Usually, components can be easily removed leaving others intact. For
example, to remove the crankshaft it is possible merely to drain the coolant,
to remove the engine left-hand, right-hand and front engine covers and to
disconnect the cam chain before removing the big-end and main bearing caps and withdrawing the crankshaft.
K75 model owners should note, however, that it is necessary on reassembly
to align timing marks on the crankshaft and balancer shaft gears. Since these marks may not be easily
visible from the crankshaft opening it is recommended that this task be undertaken only with
the engine unit removed. The amount of preliminary dismantling necessary to
remove the balancer shaft with the engine in the frame means that there is in practice very
little extra work to remove the entire unit and gain much improved working conditions.
Owners of all models should note that if a major overhaul is to be undertaken, or if more than one component requires attention at anytime, the engine unit should be removed from the frame. This is
a basically simple procedure which permits excellent access to all components
and allows the major casting's to be cleaned so that the high standards required for successful rebuilding are
maintained.
While notes on alternative procedures are provided where necessary, this Chapter is based on the assumption that the
engine/transmission unit is to be removed from the frame, that the engine
will be separated from the clutch and transmission and that it will be completely
overhauled.