I just drained the gas, and put 87 in, with some seafoam, and boy, she runs way better, hard to describe, but just feels better overall. Its probably the placebo effect, I'm glad I made the change.

Sauvage is right. I was reading that yesterday for the ninja and they pointed out that in most non US countries that 91 is equivalent to US 87.

A few things:
There are/were two ways to rate octane-know as Research and Method.
One way, the octane way mathematically calculated. The other way, a motor with a variable compression ratio was used to test a fuel. Basically the motor would run at higher and higher compression until it detonated, and given a rating that way.
If you look at a '70's VW Beetle, which had about 7-1 compression ratio, the sticker under the filler cap said "Use Regular fuel, 91 Octane". Which to Americans now, is contradictory.
What happened is that decades ago, the USA decided to average the preferred US and Euro rating systems. When the new system came out, the pumps would say 'R+M/2', meaning an average of the two.
So, yes, 91 in current US fuel is closer to high test was in the old days.

Ruttly-in response to your comment about people mixing fuels of two octanes to get a higher one, there was a reason.
When the US gradually switched from Leaded fuel (Tetraethyl Lead) to Unleaded, there was a time when stations offered Unleaded, Low Lead, and Leaded.
Only a little bit of lead is needed to boost octane.
So, the gag was to use 3/4 of a tank of Unleaded high test, and 1/4 tank Leaded regular. The lead in the leaded brought the octane of the octane of the unleaded stuff even higher. So, the mix had a higher octane than either of the bases.
I remember doing that for a while  
No leaded gas at the pump, except in some Marine or Aviation places, so this is no longer done.

Higher altitude means lower air pressure. Lower air pressure means a less dense incoming charge. So, all else being equal, the motor is effectively running a lower compression ratio in higher altitudes.
This is why the Germans spent so much time on supercharging their airplanes preceding WWII. It was the only way to restore lost power at higher altitudes.
So, theoretically, the bikes should be happier on lower octane at higher altitudes.

As for carbon removal, cold engine , start use seafoam in a spray bottle and just mist it in turn it off let sit awhile then repeat dump unused portion in fuel tank
Also GM has a top engine cleaner works well too !

Kris,
It's not about making sense, it's about chemistry.
Kinda why I said:
"Only a little bit of lead is needed to boost octane."
The lead in the leaded gas boosted the octane in the high test unleaded.
A moot point these days, but it did work.
FWIW, the guy who told me to do that was a former NASA scientist who built the BMWs and Hondas that won the US Superbike titles.
I kinda figured he knew what he was talking about.

Hekkuva idea,