Hi Dirk -
I just checked out your site - it's great, and I wish you guys an eventful trip.
On the tank subject for the F650 GS PD, I cant use the Acerbis 27l option , as the tank on the GS PD is fake, the real one lying beneath the seat. The only option I can see is still the touratech one worth 2,400 DM!
If the fuel economy is correct on the GS PD as you describe, perhaps I'll just wing it on the standard tank, and buy a 5 litre plastic tank when the need arises.
The next question I have however - is regarding the Cat converter. If I do use leaded fuel I understand the converted will be stuffed - but does that create any problems ? - I mean can the bike still function normally when the converter is stuffed ?