Pull your battery and head for Auto Zone. They have (IRRC) "powersports" batteries, for all manner of ATVs and motorcycles. They are dead ringers for OEM batteries. Just show the clerk your battery. Place your battery on the counter next to the new one. If the connectors, voltage (12), and case size are identical, you are good to go. Auto Zone carries YUASA batteries, a major producer of OEM units. Quality is excellent.
You'll pay far less than for an OEM unit at the dealer, and you can drop off your old battery for recycling right there.
Another advantage of buying a battery this way is that you add the electrolyte (acid/water mix) yourself. It's included in six little tip - in vials. This way, you know that you are not getting a sulfated battery that has sat on a shelf for months if not years.
Yes, it's still a maintenace free battery.
This is also a good opportunity to buy a float charger, if you don't have one. You'll need it to put the initial charge on your new battery. I like the Schumacher SEM-1562A. It is under $30, of high quality, and selectable for 6 or 12v, handy as I have a WWII jeep with a 6v electrical system.
Have you considered dropping about 6 pounds and installing a Speedcell battery. Check out Motowheels in the sponsors section. I picked up one for my Streetfighter. Some guys are putting their own batteries together that are of the LiFePO4 type. My new battery weighs 1.7lbs!