For people looking to do this pass in the future the post above was very helpful. I think a few things have changed and the road conditions are a bit better - I think a lot more of the Chilean side is paved now and the gravel bit is super easy.

Very beautiful but cold and windy, at least it was when I went. Fuel, about 470 kilometers in between stations so take a jerry can if you don't have the range - I bought one an 11 liter one (which I really didn't need but figured it's better to carry extra gas than run out) at the Copec in Chile for 3800 pesos.

There are five or six emergency shelters on the Argentinian side, which were awesome, in between the aduana and the closest town Fiambala... pick one they're all free. There is also an abandoned tourist resort after the fourth shelter which I'm sure you can stay at.

I stayed at Refugio No 4 and there was coal, cigarettes, a lighter, and other random bits. Anyway, they are free and it's nicer than pitching a tent because it gets you out of the wind and they are quite warm. I also saw the Carabinero place on the Chilean side but didn't stop there.

Argentinian aduana guys were cool and I got camping water from them. There was also a hotel at the top, just a few hundred meters before the Aduana and the guy said it was 40 pesos the night.

Make sure you either have dollars or Argentinian pesos because they don't take Chilean pesos; however, there is an ATM in Fiambala so you can get money and fill up your tank.

I have a KLR and had no problems with the carb or air intake - however, I was going slowly and taking lots of pictures so that may have had something to do with it.

Good luck and have fun!

Hi 4th December 2014, Im planning to Ride Santiago to Buenos Aires via Mendoza. Then up to Iguazu Falls. Does anyone know the frequency of fuels stops along the way ?
Does everyone carry spare fuel ?

hola bartman
don't worry lot's of ypf(gas station) on the way only bring enough $$$ to change in argentina very cheap fuel here.