Honda HSM1380i Manuel De L'utilisateur page 120

CAUTION:
When disconnecting the battery cable, be sure to disconnect at the battery
negative (–) terminal first. To connect, connect at the positive (+) terminal
first, then at the negative (–) terminal. Never disconnect the battery cable
in the reverse order, or you may cause a short circuit if a tool contacts the
positive terminal.
NOTE:
When you replace the battery, do it in pairs.
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