Modern Vespa

I changed my battery fully 2x this week but my 2005 ET4 will not start, it did start briefly twice, once it stopped…
attempting to start again
battery goes dead before it does.
The YUASA YTX-12BS is only 1 year old and always taken out when not in use… and kept on charger periodically.
I've read in forum and online that this is best battery for my bike ..so what the heck?!! Not cheap and didn't last long.
Lookin to buy a good battery in NNJ
Which one and where?

Can you describe what's happening when you try and start it with the battery fully charged?

Typical sound of trying to start but doesn't fire up! As I said, it did start but didn't stay idling and turned off when I tried again battery does have enough to get it started again. I changed battery night before to full.

Ok, so that sounds like you are draining the battery trying to start it.

You need to sort out the non-starting rather than getting another battery, all that will happen is that you'll drain the new battery as well.

Have you checked things like spark plug, fuel etc

Will check both. Does it make sense that the battery would die within 2-3 mins of trying after having a full charge? .. even if the issue is gas or spark plug.
The bike ride perfectly smooth prior to this cold week I might add.. no timing issues or backfiring.
Should I try jumping w/ cables.. that would tell me the battery and not anything else.

I would take the battery to a Batteries Plus store and have it tested under load. Charge it as much as you can, before you bring it in. I get most of my batteries from Batteries Plus. Not always the cheapest, but they're reasonable and they've always had the battery I need in stock. Plus, they can give you a replacement right away if you battery fails under warranty.

I've also found it handy to have a DMM (voltmeter) around to diagnose battery problems. You can find them for around $10 at Harbor Fright and other places.

You could try jumping it from a car battery -- but don't have the car running when you do. You could fry the scooter's voltage regulator.

yes, it would. any more than about 20~30 seconds is putting tremendous strain on the battery.

more than likely your battery is shot. you've got volts, just no amps. you can take it and have it load tested to be sure but the likelihood is that you're in for a new unit.

further more, you may have an underlying electrical issue. a charging or drain might be in play here.

2-3 minutes and the battery is empty is too short. Probably your battery is not in good condition.

But in these 2-3 minutes, does the starter engine then run normally? Or also weak and slower than normal?

If it runs normal the engine should fire up within like only a few seconds or even shorter.
Then you have 2 problems: a worn battery and something else.
Maybe because the engine started up very easiliy before is why the bad battery condition was not noticed.

Starter sounds same as usual Strong

well, up the diagnostic tree you go!

you got a flash code on the LED?
fuel, spark, compression?
no air leaks?

start poking and prodding, see what turns up.