The danger of inhaled silica is not that of toxicity, but the shape of the particle when in macroparticle form. I would hope that the compound has been thoroughly tested before being released to the public.
A small to midsize motorcycle will have no problem getting fifty miles to a gallon, and they get to skip the "Gentle Run" part of the equation. On a loaded touring Harley I have seen people get upward of forty miles a gallon, once again without having to hold back. My girlfriend's small, 35 year old Honda gets easily seventy or eighty miles a gallon around town. My larger, 40 year old Honda gets somewhere around fifty or sixty without sacrificing rapid acceleration.
A small to midsize motorcycle will have no problem getting fifty miles to a gallon, and they get to skip the "Gentle Run" part of the equation. On a loaded touring Harley I have seen people get upward of forty miles a gallon, once again without having to hold back. My girlfriend's small, 35 year old Honda gets easily seventy or eighty miles a gallon around town. My larger, 40 year old Honda gets somewhere around fifty or sixty without sacrificing rapid acceleration.