Vintage Tiger wits end

Firstly, hello this is my first post to this forum. I cannot believe that you have to PAY to post to that other well known forum!! Are they serious?

Can anyone shed some light on my 05MY 955i Tiger? It's currently waiting at the gates of disposal because I'm at a loss as to what to do next and I've pretty much had enough of it...

I've replaced the entire charging circuit and components from end to end. The battery, regulator, stator, fuse box and all the wiring has been renewed. The only thing left to change is the rotor and they are a million pounds each.

It starts - it charges at 14.v. When it warms up, that drops a bit but still shows a good charge. But then this gradually drops off to nothing and at idle the volt meter starts to drop 12v/11v/10v..... If I switch off after an hours ride, it isn't going to start again.

What would you do?

 

Stays fully charged with only the clock drawing about 0.1 amp