Confetti and rubber bellows.

I may have mentioned this before, but when BMW attempted to solve the inherent problem of shaft drive on a motorcycle (the rocking horse effect of the whole bike being jacked up or down during acceleration and deceleration) they came up with a torque reaction arm mounted underneath the swingarm and linked in such a way as to look vaguely like a parallelogram: they dubbed it the "Paralever". 

While this certainly helps counter the annoying effect you'd experience on anything prior to this series, this necessitated introducing a joint between the driveshaft and the rear final drive where previously there was none. And this meant removing oil from the driveshaft (replacing it with grease instead) and limiting oil only to the final drive bevel gears, locked away be means of a seal around the pinion.

I thought about this as I looked at the oil sprayed around the rear tire somewhere in Sulmona:

Oil galore! Oil everywhere!

So, it's entirely possible that the seal as well as the rubber boot have failed.
Luckily it all held up fine and we were able to complete our nearly 400 Km tour:

The weather was nothing short of ideal, for the engine at least seeing it was cool and with low humidity. Chilly at times, especially at higher altitude, it meant we had to stop a couple of times to add layers and get out of the wind for a little bit.

The historic city center of Sulmona is pretty, decently kept and with an impressive background of mountain peaks wherever the view opens up beyond the buildings.

The city is famous for its confetti, which we sampled with mixed results.

Two particularly noteworthy stretches of road during this trip were the climb from Collarmele to Raiano and the upper section of the SR479.

Touring two-up across these landscapes is a very different experience from what the guys and I typically do, much more leisurely for sure; it also makes me think I should set up an intercom system so we can talk as we come across new views and those little details that are sometimes easy to miss. It might well be an upgrade for our next trip.

Safely back at the Monolith, it's time to figure out what to do with these BMWs: the R100GS needs this leak sorted out, as well as a new rear shock absorber and eventually new tires. The gift horse is driving me nuts and I simply don't have time to sort it out. I know what needs to be done (new HT leads and caps, checking the coils and replacing if needed, checking the choke mechanism at the carbs, then move on to timing it with a strobe gun) but I may need to outsource this if I ever want this machine on the road, we'll see.