Motorcycle Repair: charging system

Question
On 1998 Honda shadow 750 ace voltage goes down when I rev the engine what could cause this to occur?

Answer
Hello Oscar,

Have you measured the voltage at the battery? How low does it drop?

Usually when voltage drops as rpm rise, the problem is somewhere in the connections.
All of the charging system's components must be checked in the following order:
Battery (load test), alternator (no-load voltage), rectifier/regulator.

But first, measure the battery voltage with the main switch off, with the engine idling and with the engine at 4000rpm.
Get back to me with the measurements and I'll let you know what to do next.

Best Regards,
Lazaros.