It was a dirty starter motor!
 

Hi all,
Update on the bike after the service.
We left the bike with Berlin Moto's in Tucaman and told them that the starter had apparently been playing up according to On Track Moto's in Salta. They said they would look at it for us on top of the normal service routine. All was reported as good when we picked the bike back up and they confirmed that On Track had looked at and serviced the starter motor. Their diagnostics computer didn't report anything either, not the overheating or why the engine cut out at 5000 mtrs on the Paso San Francisco. However, I do think that was down to us not being able to get enough speed up on the ripio to feed air into the oil cooler and what little oxygen there was into the engine.
Today we left Tilcara in Northwest Argentina (at 2,300 Mtrs) and are taking the Paso de Jama back into Chile and San Pedro de Atacama. We have been running at around the 4,000 Mtr mark for most of the day :freezing:, albeit on tarmac, and have had no problems.
Hopefully we will have some smooth running before the next problem hits us :oops2:
Thanks again.
Kev & Lorraine

I hope it isn't a fluke, otherwise there is nothing to be learnt here.

I'm reading this thread with interest so if you do get more insight into the exact reason of the failure(s) then please post them.

I for one don't like surprises, at least not ones that i can't fix.beer

As far as I could make out with my limited Spanish the problem was that with all the ripio we have been riding dust and dirt had gotten into the starter motor clogging the brushes/contacts and therefore not allowing the starter to turn. Maybe if I cleaned the bike more often would've helped ... lol