Key info on the the battery is to have approx 12.8 vdc after fully charged and no lower than 13.8 or above 14.8 while running (charging) . The noise you are hearing is probably the Compression releases clicking. It doesn't take much power to trigger them. The starter solenoid and starter are what needs the punch. The 12.3 vdc you have may be enough to make the solenoid activate but definitely not enough to crank the engine.
When the start button is selected the CR's are triggered for one second along with the starter solenoid getting voltage to operate the starter. This helps reduce the load on the starter for easier starting.
If your looking for a new battery the DEKA EXT20L is a popular choice. Mixed reviews on Lithium batteries as they seem to cause issues with the EHC smoking.
If your bike doesn't have a Circuit breaker or fuse between the battery and EHC it is good advice to put one in. Stock bikes did not come with one and it leaves the EHC exposed to a shorting battery.
That's my

and Welcome to Bigdogbiker
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Thank you, do these backs have a momentary switch because I’m basically having to redo this harness