What year is my cb 550 please

[deltarider]

Thought so…it’s featured in the workshop manual.

That's not necessarily what p.17 in the Parts List is about...

[Sesman]

You’ve lost me there. It was the change to clutch disc that interested me and it’s featured in both documents…unless I’ve missed something, which is entirely possible.

[deltarider]

From where that particular modification came into effect, is clearly indicated in the Parts List by specifying the precise engine number. Not in the Shop Manual.

[Oddjob]

Yes the double plate Bryan.

Odd, the supplement has a slightly earlier engine number than the parts list for when it changed.

[Rolfbulmer]

Thanks Bryanj, carb tops are coffin shaped with screws either side.
Thanks Oddjob, swing arm is fully enclosed.
So with all the great replies I've had my conclusion is that I have a 1977 F2.