Honda-SOHC

That sounds about right but I haven’t managed to get the old stems out yet. They are currently sitting in the garage soaked in WD40 so I’m going to have another go at them tomorrow - I may have to apply a bit of heat.
In answer to your previous question I would be happy to take the used pair off your hands at the price mentioned. I think these will be more in keeping with the rest of the rebuild as I am trying to use as many of the original parts as possible to have a ‘sympathetic’ restoration.

Many thanks for the help guys, particularly the info regarding part numbers. I have got a useable right hand ear, albeit quite rusty as the bike sat in a shed for over 20 years after my mate pranged it and got it well and truly written off. The left ear however is in a couple of pieces as it was that side of the bike that took the full impact in the crash.
I think my mate had kept the wreck in the hopes of one day getting it back to its glory but unfortunately he passed away at the end of last year and the bike was found in his garden shed so a couple of us are trying to restore it as a tribute.
My preference would be to source a matching set but the priority is to at least replace the left one. I’m happy to pay up to £150 for a decent second hand set or around the low £200s for NOS.

I received an email from a member named Roo but I’m unable to message you back as, rather weirdly, your contact details didn’t come through with the email.

I have just started a rebuild project on an accident damaged 1977 CB550 K3. I have already had to buy a replacement crankcase from a ‘76 model which will give me a new engine number but, unfortunately, the bike was a category B write off so I have also got to source a new frame. The only one I can source at the present time is a USA import (not sure of the year) for which the seller says he has the necessary NOVA certificate.
Can anyone advise how easy it will be, or even whether it will still be possible, to obtain a V5 and an age related registration.
Many thanks in advance.