The leader of the Junkions made his first appearance in the original (and greatly superior) TRANSFORMERS: THE MOVIE. He lives with his fellow autumn-themed motorcycle robots on the Planet of Junk, or Junkion, episode depending. The series never made that entirely clear, as both are used interchangeably. One should take into account that the Junkions are a difficult bunch to get a straight answer out of. Anyone who thinks "Oh Cisco", "Oh Poncho" is a romantic exchange and has laser guns built into his nipples is going to turn off a lot of people. It's the handlebar antlers that tie it all together for me though.
See the entire gallery at Sector70.com