I made some enquiries thru Battery World in this regard .... they said that the technology wasn't quite there yet.
I think that would have an interest in selling me the product if it was ready.
Having said that one of my friends has been using one in his Laverda 1200 without problem for some time but he also has a Zane Laverda 750S and has had 2 of the small lithium batteries melt down in this machine.
Apparently the charge circuit voltage must be spot on for success.
I believe that Xtian may be more helpful in this matter.
I am keen shed some weight from this area myself.