I work on my 2012 KX250F downstairs in my basement. Sometimes I have to run the bike and I would have to wheel it near the stairs that go outside to do so. Any hints on where to get a hose or system to be able to vent the exhaust fumes about 20 feet outside without moving the bike?

 

Maybe try an aluminum dryer vent tube. You can't use plastic.

 

here ya go..... although it is sometimes the other questions that will kill ya.

Open the window? 20 ft is a long way. A booster fan would be a cool thing to incorporate.