I hear a squeak or whining sound when I'm slowing down to a stop (about 20 mph). Can't hear it at cruising speed. Could this be front disc? Anything else I should look at?

 

I hear the same thing on my 2007 1200C... At first I thought the noise was coming from my key/ignition rattling but now I think it is coming from the front down tubes. Possibly there are springs in there that make a tinny rattling sound? I had forgot about it, but will probably here it all day tomorrow if I ride... Thanks :-)

 

More than likely the front brake pads are "chattering" that’s causing the squeak.
How many miles on the pads?
also did you just recently clean the bike?
possible cleaning residue left over or it could be the other way around you need to clean the front brake rotor and caliper. There are a number of things that could be causing this.
You will need to do one thing at a time to chase down the culprit. I'd start with the front brake assy. first.
Hope this helps.

 

Typical crappy HD brake pads. Replace them with a set of Lyndall, "Z-Plus" or "Gold" pads and be done with squeaks, brake dust, and poor braking. They'll last a whole lot longer also. I've got over 25K miles on mine.