Just had the battery on my '12 Yager buy the farm after 14 months from new delivery.
Got the bike in May '12 and rode thru October '12 and then placed on a battery tender thru the winter months. Restarted in May this year.
Ridden regularly from May until two days ago. Called the dealer and they told me to bring in the battery.
They put it on a charger for six hours and diagnosed a "dead cell"
(Forget the warranty - Kymco gives six months on the battery and does not include it in the standard two year warranty.)
For a replacement, they sold me a "WPS" brand, model "CT12A-BS".
Fit very well and did the job. One minor problem in the install - when hooked up it immediately blew the main fuse. A quick trip to the local auto parts store scored a new 20 amp fuse for a couple of bucks.
Cost for the new battery was $79 OTD. (Plus a couple of bucks for the fuse - Your results may differ)