https://www.ebay.com/itm/1979-yamaha-rd400-daytona-special-exhaust-chambers/124687507942
These look like FPP. Silencer mounting is weird. Never seen a set like this. If they are late production they should be embossed on the chamber body. Maybe they are period instead of later 80's?
I can't see any header flange springs.
Probably I have never seen FPP's for a Daytona so maybe they are all this way?
Still sitting at $200 (0 bids) $300 BIN with $78 shipping. Pretty good deal.
IR8D8R
I would guess someone made those flanges and possibly altered that odd can mounting. I wondered if early FPP myself, I have brochure will dig it out.
They appear to be early FPPs. I have a set of them for my H2. He welded spring perches on them like I did because they have a tendency to depart the aircraft uncommanded. The clamps were not designed well. The early pipes had big in my opinion garish blue decals on the cans that identified them as FPPs if memory serves. Then later they embossed the belly of the pipes.
some fpps silencers had spring tabs welded on at the factory, i know, i had a set wayyyyy back. I can not comment on it further than that though.