Since doing a frame swap with Long deKlein, I am now the "custodian" (who owns whom with these bikes?) of this frame. I'm noodging the thread to add some info that others might find of mild interest:
Weight-wise, it's not a lightweight by 80s standards: bare frame except for pressed headset races weighs 2635 g, and fork in same condition weighs 966, putting it just over 3.6 Kg.
Seatpost hole measures 26.7; after I hone out some of the crust, I think that a 26.6 will fit -- it came with a 25.4 that was definitely too small. That makes the tubing 0.9 mm wall thickness, and judging by the frame weight, it's probably straight-gauge. Robert Broderick's gallery includes a 1950s Reynolds catalog, containing both butted and straight-gauge 531 tubing, and also an "A" line that is probably mild steel.
Geometry is fairly standard "relaxed-road": 72-degree seat tube, 43.5 cm chain stays, 63 cm seat tube C-T with 57 cm top tube C-C; that's good for me, a high-waisted guy.
BB is 68 mm wide English thread; cups marked TDC. The fixed cup came out most unwillingly, but a newer one spun in easily, so there may be corrosion on the fixed cup threads.
Brake clearance is typical of old 27" wheeled bikes set up for Weinmann 610 and 750 brakes: 368 mm from axle to brake hole on front, 375 rear. Fork steerer tube is 233 mm - 194 head tube height = 39 mm stack; good if a replacement is needed.
The original color of the bike looks like it was a medium gray-blue -- not as light as the "Azure blue" San Remos and other Falcons. Fork has chrome socks, and the crown also appears to be chromed, but nothing on the rear.
There are a few wear-and-tear issues: minor ding in top tube that body putty will fill easily, someone reefed down on the rear brake nut and squashed the bridge somewhat (not helped by that tube having a seam on the bottom). I'm wondering how much trouble that is to replace. Same story with the little chainstay bridge right behind the BB -- I don't know what kind of fixture might have been installed there that has flattened the bottom side of it. But I'm very far from complaining. I wanted this frame because it was obvious from the photos that it has the simple elegance of a workaday task done with care. The craftsmanship just radiates from it, even though the materials are not special.
As to the Falcon attribution, I think that's problematic. Coventry-Eagle became Falcon in 1970 as far as I can tell,, and I have a suspicion that this frame is older than that; mainly because of the oil port on the BB (though none on the head tube). I did find a Coventry-Eagle on the Internet that is the most like this frame of anything I've seen:
Posted here:
http://www.bikecult.com/works/archive/04bicycles/coventryeagleRF.html
The fork crown is flat, but the detailing of the lugs is not quite the same. Also, the other Coventry-Eagle bike I found on the Internet has a rather fancy headbadge, but with mounting holes on the two sides rather than top and bottom, like this frame.
The headbadge holes on the frame I have are vertically oriented, and on 57 mm centers. I found an eBay auction for a Falcon headbadge that claimed the hole spacing was 65 mm. Then I found another and sent the seller a question -- he responded that the spacing on his item was 2-1/4" (about 57 mm). So maybe it is a middle-range Falcon after all. I haven't seen any evidence of decals under the rattle-can paint. So far I've found the blue, some gray (maybe primer) and even black on the steerer tube, in addition to the orange. And no signs of serial numbers, either.