Kz550 battery dies when I’m riding it. Can’t figure this one out

So my bike has been working for sometime now. But I’m having trouble figuring out this issue so I can finally get it registered and on the road. When I am riding, in about.. maybe it might be a day or two the battery will suddenly die. I changed everything in the ignition system and the whole wiring harness is new. The regulator is brand new and the stater is brand new now the only thing that’s old is the coil‘s. Now every time my bike is running it sits at around 12.5 v and when I revv it up it only goes up to 13 V at most. Having a problem because it is supposed to go up to 14 at 5000 RPM if I am not mistaken. The ground is going straight from the negative terminal of the battery to the engine ground. Everything seems pretty proper. the only thing I could possibly think of is that the regulator is bad, I know it is new but it might not be right and it could be a bad regulator. To post a picture on the bottom here of the regular that I purchased from ricks Power Sports. Buddy could maybe possibly help me out with this or have any info or input on this situation I would be happy to see what you have to say. I should have added the battery in the equation. I had the battery fully charged and then I let it sit for like 2 weeks. It only lost like a .5. The battery is an anti gravity battery 8 cell lithium.

Can you rig something up to monitor voltage while riding. While 12.5 - 13 v is low, too low to charge the battery. It is not so low it should be draining the battery. A fully charged battery is 12.6v.

How old is your battery and did you check the battery acid level is set to the right high?
Only one dry or low Level battery cell can destroy the overall capacity and performance of a battery.

Most likely a damaged cell in the battery.

I should have added the battery in the equation. I had the battery fully charged and then I let it sit for like 2 weeks. It only lost like a .5. The battery is an anti gravity battery 8 cell lithium.

Is there a way to adjust the voltage on your regulator?

Lithium batteries should not be charged at high amps. I only use a 0.75 amp charger when I put it on my lithium battery.

The regulator on my bike does not have a setting that will do that. Well I don’t believe it does. I have a picture of the regulator I use on the main thread post. Also my external charger is the right spec to charge my lithium. Do I need to add to my charging system to run lithium? I though I didn’t.

Your KZ550's has an old school, dumb charging system, as do most bikes. It tries to keep 14.5v across the battery, at whatever current the battery will take. I never understood having a sophisticated lithium external shop charger, which pampers the battery, then throw it in a vehicle designed for lead/acid, that treats it like crap.
EarthX batteries are the only lithium batteries I would consider using , although pricey, they have the electronics built into them to properly charge the battery.

My kz1000 build with ALL new electrics and charging system killed an expensive Shorai lithium battery in 80 miles.
They just can't cope with the variance in these charging systems.
Put a lead acid one on and no problems after that.

What state are your switches in? I recently helped a buddy out with a similar problem. Only after replacing everything else did i determine the kill switch was grounding out in the switch housing causing excess draw while running. BTW ricks motorsports makes a lithium specific regulator for these old KZs

my switches are in good condition. i dont even have a kill switch on the bike just a key. im about to call ricks powersports and ask how much voltage output on the unit i purchased. i talked to anti gravity customer service and he said the battery needs to charge between 13.8-14.2

Can I ask? What’s the draw to a battery that costs 2 or more time that of a lead acid or even a good sealed AGM. The later have performed well for me. I made poor choices in brand and learned the hard way but nonetheless I don’t think I could pay way more for an item when a less expensive was available and potentially marry better with the bikes charging system.