Look like old TZ or maybe homemade. I assume he took off a Daytona since he says that what their for but I don't see any mounts. -- https://www.ebay.com/itm/D-1979-Yamaha-RD400-Exhaust-Muffler-Silencer-Baffle/283313575495?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3De21b72d319894935b2981e519c8a7703%26pid%3D100675%26rk%3D2%26rkt%3D15%26mehot%3Dnone%26sd%3D293415499411%26itm%3D283313575495%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3A0a5ddb12-45ed-11ea-85b5-74dbd1806c20%7Cparentrq%3A073e6f231700aa48c3e58e44fff15684%7Ciid%3A1
I don't see how that goes on a RD or TZ.
No enough head pipe. It looks like it belongs a motor with sloping cylinders, and it's too small a diameter for a 400.