Yamaha YZ450FX 2019 Owner's Service Manual page 301

ELECTRIC STARTING SYSTEM
4. Joint connector
5. Main relay
6. Engine ground
7. Battery
8. Frame ground
9. Main fuse
10.Starter relay
11.Starter motor
12.Diode 1
13.Diode 2
21.ECU (Engine Control Unit)
33.Engine stop switch
34.Gear position switch
36.Start switch
37.Diode 3
A. Battery sub-lead
B. Wire harness
8-6