Hi, FYI to anyone asking this question in 2012,
We went from San Pedro de Atacama to Calama (about 90Km) and next day to Ollague (about 200Km) in Chile. There we crossed into Bolivia and drove to Uyuni.
(Residencial Prat in Calama (West opposite the clear plot behind the malls) was clean and safe with parking, moody owner though. Calama sucks! But it's a place you can find spares etc if you need - prepare to be ripped off though. Mechanics at Calama Firma Motos were diabolical!)
The crossing was easy, aduana and police on both sides very friendly. No costs, no issues, nothing. High altitude though but you should be used to this by now.
The Calama - Ollague road is mainly dirt, not too bad as mostly pressed, and to Uyuni also dirt, but mainly pressed.
In Ollague you will find petrol (probably) but only by asking people in the shops or food places (they sold for 1200/litre) or more likely, the hostel Atahualpa (the best one there) but there it will be double the normal price (1600/litre). So good if you can take enough spare to do the 250-odd Km to Uyuni.
Scenery on this route is fantastic!!! Well worth the route.
After Ollague the next petrol station is in San Cristobal and then Uyuni.
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Our Worldwide Motorbiking Experience Notes: India, Laos, Chile, Argentina, Bolivia, Peru, Ecuador, Colombia, Brazil