I thought about buying one for my old BMW airhead a few years ago. It doesn't get ridden much and I thought a Li-Ion battery might tolerate that better. When I saw the price (2x or 3x of a lead acid battery) I decided to use my battery maintainer more regularly.
I have used lith batteries 2x on motorcycle. Honda Sabre and Indian scout bobber. Dealer talked me into the first one.Great results on those bikes, the sabre 9 yr old in sons bike and he never uses maintainer I bought for it .Always starts.The scout simply wouldn't start in cold weather with factory batt even maintained.So after warranty expired put lith in a ND boom everytime start.Having said that I probably wouldn't use in the f6b cause they start and last so well.