I bought this off of CL last month. I can't figure out what model it is though. I've spent a while looking through old threads, but I can't find anything that looks similar to mine. It doesn't actually have any Miyata decals. The original owner who I bought it from said it's a 1974 Miyata. That's all he knew, so that's what I'm going on. The serial number is B429510. Any help would be appreciated.