Thanks guys, was looking for some real life experience with the mountain men out west. I likely won't have much extended time above 5000-7000 but wanted to know what to expect.

 

You have to remember that stock jetting is lean to begin with. With the addition of ethanol that leans it out even further, you bike may run with its best mixture at altitude. The air would be thin and you would loose power but the mixture should be better than down below.

 

The guys who ride the 1000F regularly at 5000 ft on our highlands would increase the size of the air correction jets.

I've taken my bike to Mafika Disiu in Lesotho -the highest paved road in Africa I'm told - 10400 feet altitude and she ran fine, albeit with a drop in power.

If it's just for a one-time trip I wouldn't mess with it.