[mrlmd1]

First off, you need an electrical voltage meter to tell what is going on with your battery. Your charger does not read voltage, so it tells you nothing.
A fully charged battery should be 12.6-8V. If you charge it up to that and let it sit overnight and it still reads that in the morning, it is probably OK, but the only way to tell the condition of a battery is to load test it. Charge it fully, then test it by bringing it to any battery dealer or auto parts dealer or garage, they will do it for free (after all, they would like to sell you a new battery).
If your battery sat for months in a discharged state, it may be dead from sulphation and may not survive being restored or recharged. Do not buy chemical additives sold to try and restore the battery, they don't really work or work only very temporarily, but you might invest in a battery desulphator to try and reverse that. But for the size and expense of these bike batteries, unless you need that for other batteries you have, it's not worth the expense as they cost almost as much as a new battery in this size.
Alantf's advice is what I have been preaching on here for years - heed it.

As an aside, starting the bike IS a load test - I think the starter for this bike draws something like 60 amps. So if you charge it over night and the bike starts in the morning, that's a good sign. Do not start the bike multiple times. Do not expect the battery to recharge at idle speed. These bikes have a very puny electrical system and the output at idling even for 15 min will not replace what you have drawn out of the battery to start the bike and keep it running. In order to get a significant charge out of the alternator/magneto/generator (whatever you want to call it), you need to be running at 2500-3500rpm at least, so if the bike starts, go for a 15-20 min. ride. Then let the bike sit 4-6 hrs, and if it starts again, your battery may be OK.