Help me track down this squeeling noise.

Hey J,
i would bet brakes. something might be hung up and/or the star adjuster is not quite up to par.
when you go backwards, you kinda move the hardware the other way and it shifts around (in my experience). i never bothered to mess with it.

good luck and bump. PS you still wanna get a bike?

TS, cool - i look forward to pics. sounds like a fun project. jockey shifter should be fun! it can be some work to fab linkage for the shifter and clutch though.
(i have 3 bikes though none are jockied).

wheel bearings, In my experience, make a serious howl and rumble.

if this only happens when you back up (and perhaps for a short time after going forward again), i would still bet brakes. the clamping force is opposite from normal and makes some racquet. ive had luck removing the drums and cleaning and greasing the pivot spots on the backing plate and tightening the not-so-automatic brake adjuster star-wheels.

side note: when you are on a closed road course, wearing a helmet, etc, have you tried applying the ebrake a little bit while driving at say 20 mph? that can be decent for pinpointing noises - the rear calipers on the eclipse make some chatter and doing this quiets them up for a bit.

oh yeah, the linings are ok? ive seen one corner of a brake shoe be worn (as if it dragged), while the rest of the lining was great. had i not been paying close attention (normally im too lazy to lean over underneath) i would have missed it.

good luck J.

It could also be rust accumulation on the drums. Maybe you are parked next to sprinker, a perpetual puddle, or something similar. Either way if that is the case, after a few feet or a few steps on the brakes, the shoes wears off the rust.