I wonder if some battery issues are not being caused by the cheap charger MV supply? Thankfully (?) the previous owner of mine didn't seem to return the charger when he sold the bike - forcing me to wire in and use my dual-bike optimate.
Been using Yuasa in bikes for years and not had a duffer yet. Replaced the BS (yeah, thats the actual manufacturer name) one in my F3 at the beginning of this year and hasn't been charged, other than riding it since. Very sporadic chances to ride at the mo and it always fires up like a dream (which it rarely did unless I'd just taken the original off the battery tender)
The model number Stephen gave is the one I've got.