Maybe the lead in the Gas?
Sunoco 110 race gas has lead in it, so maybe that is why you are getting a different color on your plug?
Question: Do you have modifications on your bike that require that high of octane? If not, i would be surprised if you are detonating and therefore in need of that high of octane. High octane fuel burns slower, which stops detonation.
For what it's worth.....i am able to run 9 lbs of boost on my 2-stroke turbo snowmobile with only a 50/50 mix of 110 and 91 non-ethanol pump gas. A turbo is considered a substantial modification, so that makes me think that using straight 110 in your bike is overkill, unless of course you have some substantial mods. on it as well.
Maybe a little more info on the mods (if any) on your bike, what bike you have, the plug you have in it, jetting you are using, and what elevation you ride at would be helpful.
Cheers!