The W8 engine has two balancing
shafts to compensate for the forces of
inertia. The two shafts are housed in the
crankcase. The upper balancing shaft
is driven by the crankshaft and a toothed
belt. A gear on the end of the upper
balancing shaft drives the lower
balancing shaft.
The balancing shafts are installed
through two holes on the clutch side of
the crankcase.