Bruce, With the NT's moderate compression ratio, the lowest octane you can buy will save you the most money and, oddly enough, actually make the most power. Octane is a measure of resistance to "knock," which is explosive pre-ignition. Anti-knock compounds actually reduce the power in the cylinder's fuel charge, but since engines that need higher octane have higher compression ratios, they make more power by not having to deal with pre-ignition.
But with your NT, the lowest octane rating is the best. Out here in the mountain west, where altitudes are higher, we can buy 85 octane gas and it works fine too.
The reason is that with the thinner air, we are compressing less air, so we don't even need 87 octane. Last Monday I took an airplane ride with a friend who has a high-tech engine monitor. His plane is a Cessna 182 with a 230-hp Continental. Full throttle with full rich mixture and the prop turning its red-line (2600 rpm, IIRC) would give that 230 hp at sea-level with standard conditions. But here at 4500 feet, the same 2600 rpm, and full throttle only gave, according to the engine monitor, 87% of max hp for 201 hp. I noticed that my friend used full-rich mixture, and might have gotten a little more power if he had leaned to 50 degrees above peak temperature. But a bit of extra fuel makes the engine run cooler and that gives longer engine life.
With the NT's fuel injection, we don't have to monitor as many factors as pilots do when they're flying engines without all the electronic wizardry.
BTW, as far as I know you don't need fuel additives to protect the engine like you used with your KLR. With the KLR, you've got fuel sitting there in the carburetor evaporating its most volatile compounds and getting "gummy." With the NT, it's not doing that.
Congrats on a great bike and welcome to the Forum!
