I was going to say...is that an RD400? They were an object of lust for me about this time, umm, some 40 years ago...still like the look of them. But haven't seen one on the flesh for years
J.
Mine was the 1976 RD400C, first year of the 400s. When I was young the RD350s were considered a total weapon, a 750 slayer. When the 400 came out, it was all that plus a good bump in low-end torque (relatively speaking of course). Again, it's all relative, but the top end was a mad rush. Back in about 1981 I had a Kawasaki KH500 (H1) and they truly were as terrifying as legend held. Mostly because the chassis was no match for the 3-cylinder 2-stroke. By comparison, the Yamaha was composed.
I bought the one in this picture (c. 2000) from some guy hording vintage Yamahas in an air hangar down in Charlottesville, VA. He was far more interested in the old DTs, so it didn't both him to let this one go. The RD400 was completely original with about 14K miles. All it needed was a minor rebuild, easily accomplished with NOS parts found at swap meets. She ran pretty nice.