A story copied from the El Camino Forum (El Caminos rule, I now have two):
I always rode my bike on New Years day (what better way to start the year?). One year, in far western suburbs of chitcago (Wheaton), it was -55*, and THEN wind chill on top of that. I was gonna go to Indianapolis on the bike for the Frozen Butt ride, but after 7 miles, had to turn around and go home.
I was dressed in 5 layers, and the entire outer layer was rubber (incl snowmobile goggles), so I really didn't get cold. But it was so cold at 40 MPH that the body on the aluminum carb would shrink, not allowing the butterflies to close when I let off the throttle. I had to hit the kill switch, coast to the side of the road, and after about 30 seconds, the engine heat would warm it up enough that I'd hear a "thooop" as they closed, and I could start it up and go on. At that rate I knew I'd end up in the back end of something, so turned around and went home.
I had a bright yellow rain suit (jacket and bib pants) on. When I left, my gf said to be sure and watch for traffic. I told her I wouldn't have to, and she asked why not? I said, "because everyone else on the road will be pointing and saying "LOOK AT THAT IDIOT!" and they were!