I'm a bit of an RD anorak, had way too many of them all for my own good. There's been a few YDS7s and YR5s pass through my hands, and even a YDS3 and a YDS6. Most of mine have been RD400s, and most of those were E or F models (29 400s all told).
I love them to bits
By the way, your 250B had the wrong clocks fitted. The ones it has there are from a D or upwards model. It was a US import too, it had a round rear light and frame reflectors.
