Looks like this is one of the bits made from Unobtainium, a 8 valve cylinder head for the CB450.

A decade ago I did some serious investigations, trying to get get in contact with, what I believe was, the  last man standing, that was involved in making this conversion kit. I have to say I came pretty close, but...

Last year I made another attempt approaching from another angle, so to say. Seems like guys that could help are not interested in helping at all. Ignorant is the word.

Anyway, this is what I was searching for.


  1. Hi,

    Did you get any further with this? I am helping investigate the same head for a friend who is going to get one make if he can get enough info. I have some pics of the internals, if you are interested?


    Petermichaeljones@hotmail co uk

  2. Peter, you've got email.