Hi Tom,
I removed my AI at 26,000 miles. The pipes had no blue on them at all at that time. Of course, my left mix screw was 2 turns out and my right one was bottomed out the whole time from the factory, I just didn't know to check.
Maybe it was the shrouded header? I imagine that on the standard Bonnevilles and T100s, this would be a reason for quick bluing.
Dennis
