Here is one link discussed last October
MPG Also, I just finished 2 500mile days...all Interstate...78-80mph (real speed) and my MPG's were at 45, 42, 40, 41...all related to how fast I was going.
I find as the summer heats up I get better mpg...last year I often reached 50mpg.
Pipes are Specialty Spares...jets are ..hum...can't remember.

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Oh yeah, I had on my big Memphis Shades shield for the trip which really fought the wind...definitely impacted MPG since I usually ride with the Memphis Alley Cat.