Inspected the electrolyte level ? What century are you living in ? the one that on a ten year old bike that it may have had a replacement wet battery fitted in its life which when tipped can loose its electrolyte through its vent . Same as a sealed maintainence free battery can leak when tipped As with any fault finding you check the basics first . Sorry mate , I didn't mean to offend. I did check it , its a YTX12BS which is a fill it yourself sealed battery ( now banned ) I suppose you could substitute an old lead acid battery but it wouldn't be a great idea especially if it is not installed upright. It's most likely to have a pre sealed version nowadays .