(not mine) - Listed as a '77 but sure looks like a '78 with "Yamaha" logos added to the calipers. Can't see the serial number to confirm
https://slo.craigslist.org/mcy/d/paso-robles-1977-yamaha-rd-400/6869612909.html (https://slo.craigslist.org/mcy/d/paso-robles-1977-yamaha-rd-400/6869612909.html)
1977 Yamaha RD 400 - $3850 (Paso Robles)
400cc duel cylinder 2 stroke engine
Extremely powerful, and very quick!
I wonder if this owner routinely repairs and sells RD's? It seems that I have seen similar ads of RD's taken in this yard over the years.
It's a great looking '78.