Special Tool - Outside Circlip Pliers: 57001-144
The 5th gear [A] on the output shaft has three steel balls assembled into it for the positive neutral finder mechanism.
Remove the 5th gear as follows.

Set the output shaft in a vertical position holding the 3rd gear [B].
Spin the 5th gear quickly [C] and pull it off upward.
Transmission Assy Installation
Transmission Shaft AssemblyValve Guide Installation
Apply engine oil to the valve guide outer surface before
installation.
Heat the area around the valve guide hole to about 120
150°C (248 302°F).
NOTICE
Do not heat the cylinder head with a torch. This will
warp the cylinder head. Soak the cylinder head and
heat the oil.
Usin ...
Lower Crankcase Assembly
Install the ball bearing [A] and the oil level inspection window
[B] until they are bottomed
Apply soap and water solution to the oil level inspection
window before installation.
Install the new circlip [C].
Apply a non-permanent locking agent to the oil passage
plug [D].
Tighten: ...
Lower Fairing Installation
Installation is the reverse of removal. Note the following.
When installing the pad [A], align the edge of the pad and
the marking of the fairing [B].
When installing the pad [C], align the edge of the pad and
the fairing [D], and fit the edge of the pad to the boss [E].
Insert the hoo ...