I - (Interstate) - When on a long ride one will say, I had to ride the "I" from such a place. Or like me I hate the "I's". I'm a backroad rider."
Ignition - The way the fuel is ignited inside the engine. This is normally archieved by a spark from a sparkplug.
Indie Shop - Independent, not franchised
Indicators - Turn signals/blinkers in the UK
Ink Slinger - Tattoo Artist
Inline Four - An inline four cylinder motorcycle (or automotive) engine, these are among the most powerful motors on a motorcycle
Insta-Biker - Anybody who goes down to the local bike shop and buys the Bike, Gear and fake tattoos so they can hang out with their new ""Bros"" (also Poser or Poseur)
Iron Butt - An entire association was created called the Iron Butt Association -- 1000 miles in 24 hours yields a Saddle Sore 1000 - Bun Burner is 1500 in 36 hours, Bun Burner Gold is 1500 in 24 hours. The Iron Butt Gold Is 10 days x 1000 miles each day - consecutive. The challenge for this award is run every other year.
Iron Butt 50CC - A coast to coast endurance ride, for example, Jacksonville Florida to San Diego California in under 50 hours
Ironhead - The first generation of Sportster models (produced from 1957 until 1985). Unlike other models with nicknames that describe the look of the cylinder heads on particular engine ("Knucklehead", "Shovelhead", "Flathead", etc.), the Ironhead name comes from the fact that the cylinder heads on these models were cast iron whereas the heads on other models at that time were made of aluminum.
Ironside - Towards the top of the bike, or top area of a part or component