Quote Originally Posted by Tuckervill View Post
I wish I knew what to look for as far as the serial number. It should be obvious on the bottom of the bottom bracket, no? I couldn't find one on the John Deere, either. And there's that big rusty spot on the BB. I seem to recall people stealing bikes and scratching the serial numbers off them when I was a kid. Maybe that's why this is rusty.
You could be right about the serial number being ground off, and the resulting rust on the BB. They normally don't rust up that badly.

It was normal to find lots of Japanese parts on European bikes by the mid to late 70s, but not in the early 70s. What you have is intriguing because the Suntour Sprint and GT derailleurs were early models, superseeded by the V-GT, and I don't know of those being used on European bikes. European bikes in the early 70s were using Huret and Simplex shifters. Though Diacompe brakes were standard on Motobecanesthroughout the 70s. The crankset is also interesting, as it's cotterless. Low end 10-speeds from Europe didn't go cotterless until the late 70s. I'm leaning towards Japanese on this bike. Japanese bicycles available in America would have included: Nishiki, Centurion, C. Itoh, Fuji, Panasonic, and Sekai.

If the headset is labeled, there may be some writing on an outside cup, but the threading specifications would probably be inside. If the bike is Japanese, the frame cup outside diameter would be 30.0 mm (European would be 30.2).