It could be any of the above listed items, but there's not much point in guessing until you know what your battery voltage is.

If it's still on the tender, disconnect it.
Turn the ignition switch to ON for 5 seconds (lights on), then turn it OFF.
Now measure your battery voltage. If it's less than 12.6 - 12.8 VDC, chances are the battery is bad or the tender is defective.

 

Yea like all say check you battery voltage, if it is 12.6 or better as it should be with a new battery and you have checked all your connections, then next step is to check the amperage draw of the starter. I would take it to any shop that rebuilds starter for this test, they usually will do it for free.

 

conclusion here:

it was the battery... the old one and new one both showed that they charged fully within half hour on the tender. but the old one tested bad and the new one tested as the wrong one for the bike!
got a new battery compatible with the sporty and all is well-
I was very surprised to find out that the old one could show that the tender fully charged it but it was still bad...

thanks everyone for your input-

 

Recently ran into the same thing with a new (6 week old) aftermarket battery. Voltage showed good on the multimeter, and tender would go into float mode, but had very weak turn-over when trying to start, often not starting at all. Had it load tested at 2 places - one said it was good, the second said bad. Replaced with OEM HD battery and have had zero issues since.

 

sounds same as my experience... I still wonder how that can happen-

 

There is a big difference in voltage and amperage of a battery, when buying a battery it is important to get a battery with a high enough cranking amps for your bike. You can hook up two nine volt batterys in series and have 18 volts but it wont be enough amperage to start a Harley.
Think about it like hooking a garden hose up to a water line with forty pounds of pressure and a fire hose to the same line. The fire hose will have the same pressure but do one hundred times the work cleaning your drive.
Same with aftermarket batteries, you need to check the cranking amperage. I Run the Big Crank with the highest amperage that fits in my bike.
When doing a load test it is important to know the demands of your starter, just because the guy at discount says it is good, that wimpy battery that he sold you might start up a moped, but give out trying to start a real bike;-)

 

thx harleycruiser nice explanation... I get it now