I checked it after I had charged it and resting it was 12.3 - tested it again this morning and its still 12.3 ...
Okey, batteries are a little sience and a little art, but to try to stick with the basic principles eg KISS. Most people have or are easibly able to get hold of and use a basic a voltmeter. So if you check the resting voltage (over night a good start point, or allow 4-8 hour of rest after charge or discharge dependend of amount charge/discharge of the battery) at room temperature you should get:
12.65V 100%
12.45V 75%
12.24V 50%
12.06V 25%
11.89V or less Discharged
(Some small variations between different battery types and size - and if temp below 77F/room temp expect less). So 12,3 VDC sounds low if this is after a proper full charge unless (outside) in "low temp". If the battery can not be charged to a resting voltage of about 12,7 VDC - no need to look any further you have a weak battery that need to be changed. Why that happened is an other story. With a new battery keep an eye on it to see if the bike is able to keep it charged and fit. If not, time for more investigation...
As for charging voltage of 14,3 VDC - it sounds about right, but several factors are influencing this...
So KISS and Best of luck