It depends a little on which route you take. There is absolutely no fuel available anywhere between Arco and Challis if you take the Arco Pass (east) variant. There is potentially some fuel available if you take the Beverland Pass Route, but you'd have to ride out of your way several miles to Highway 93 and either Darlington of Mackay. That would be a lot of effort for gas just 15 - 20 miles from Arco.

Even with all of the variants we recommend it's only 140 - 160 miles so any bike with a 5 gallon or greater capacity ought to be just fine.