Popped the tank open again this afternoon and learned a valuable lesson, if the tank is full drain some of the fuel.
Tough lesson! This wasn't an urgent item, so could have waited until your fuel was low.
For anyone- never try to raise the tank when it's near full. Firstly it's very heavy and will be hard to pull back in the slots (important if you have bar risers).
And, as you now know, it will spill some.
If you're putting your bike in to a mechanic for a service, it's polite to have less than half a tank of fuel, and leave your panniers and topbox at home. Those little considerations will not only make his life easier, but will save the possibility of your paint getting damaged or the panniers not mounted correctly. It's relatively easy to mount them wrongly if you're not familiar with the ST1300, and even though the latch locks down, they will come off. DAMHIK