Refer to “rear brake master cylinder disassembly and assembly” .
Master cylinder
Inspect the master cylinder bore for any scratches or other damage.

Piston / rubber parts
Inspect the piston surface for any scratches or other damage.
Inspect the primary cup, secondary cup and dust boot for wear or damage.

Rear brake master cylinder disassembly and assembly
Rear brake pedal constructionEcm / various sensors
Since each component is a high-precision part, great
care should be taken not to apply any severe impacts
during removal and installation.
Be careful not to touch the electrical terminals of the
electronic parts (ecm, etc.). The static electricity from
your body may damage them. ...
Special tools and equipment
Recommended service material
Note
required service material is also described in the following.
“Rear lighting system construction”
Special tool
...
Horn inspection
Note
if the horn sound condition is normal, it is not
necessary to inspect the horn button
continuity.
Horn button inspection
Remove the air cleaner box. Refer to “air cleaner box removal and
installation” in section 1d .
Disconnect the left handlebar switch lead ...