Bike: '99 R1100S, 15K miles, one spark plug heads, recently replaced injectors with matched EV14's. Removed the exhaust for a clutch job and found the exhaust ports on each side were TAN on the upper port and BLACK (or charcoal grey - but not sooty) on the lower port. The tan was also into the common area just before the pipe. See pics.
Does anyone know, or have an educated guess why ports would be such different colors coming from the same combustion chamber??
Closeup of "common area":