['It will fit in the frame if that's what you want to know, but you won't get the rockerbox off..']
I don't know anything in detail about the Model 18 engine but the 'Big Fin' Gold Star has the same problem...The head and rocker box have to come off together before the rocker box can be removed from the head...
However, if the rocker box studs are replaced with bolts it is possible to get it off without removing the head (which is a right pain)...Might that work for the Norton?...Ian
In the proper frame you can take the engine apart. I guessed the measurements were to see if it goes in a WD16H frame? It's tight, the bolts come out but it won't lift over the valve springs.
So what was the reason for the question, Anton ? With a little more information, you could probably have received a much more detailed answer. There aren't many things that haven't been tried in the world of old motorcycles ! :grinning:
