Do 400/4 rear mudguards /fenders fit a cb550f

[Chris400F]

My thinking/belief is that if tyre size is wider then the swinging arm is wider to allow for this and the frame tubes at the top are correspondingly wider to keep the shock mounts the same distance apart at top and bottom, but I may be wrong in this assumption.
I know when I was looking for a rack that would fit that some I looked at were too wide at the shock mounting points, being probably intended for larger bikes. Fortunately someone on here helped me out with one that was intended for the bike.
It's not easy to measure accurately in situ but the distance across the mounting points on the 400 is approx. 170mm.

[Seabeowner]

Late 550K bare frame measured as 174mm.

[Darkness]

Isn't the 3.5 X 18 rear tyre on a 400/4 (Or CB360 G5) the same width as the 3.5 X 18 tyre on a CB500-4?

Though I used to prefer a 4.25/85 X 18 TT100 on the 500.

[Chris400F]

I think it is true that the 400 has things like tyre sizes in common with smaller models such as the 250/360, whereas 500 and up have larger section tyres.

Isn't the 3.5 X 18 rear tyre on a 400/4 (Or CB360 G5) the same width as the 3.5 X 18 tyre on a CB500-4?

I'll hold my hands up - I stand corrected.

Maybe it's just a case of whether the mounting holes line up OK.