Honda SH125 Manual page 237

Apply locking agent to the starter clutch outer bolt
threads and install them.
Hold the flywheel with the special tool and tighten
the bolts.
TOOL:
Flywheel holder 07725-0040000
TORQUE: 30 N.m (3.1 kgf.m, 22 Ibf-ft)
Apply engine oil to the starter driven gear teeth and
sprag clutch contacting area.
Install the starter driven gear into the starter clutch
on the flywheel while turning
it
clockwise.
Check that the starter driven gear turns clockwise
smoothly and does not turn counterclockwise.
INSTALLATION
Install the woodruff key in the crankshaft key
groove.
Apply molybdenum oil solution to the starter driven
gear sliding surface of the crankshaft.
Clean any oil from the tapered portions of the crank-
shaft and flywheel.
Install the flywheel onto the crankshaft, aligning the
groove with the woodruff key.