Wheel swap between Z500 B3 -81 and Z650 -82

Hey!

One year ago, I needed new wheels for my Z500 B3.
I managed to find a pair from an old Z650 which were good and did fit.
Now I have bumped into a question though.

I let the old Z650 brake disks stay in place as they also did fit, but now that I wanted/needed to change brake pads, I find that the ones for Z500 does not fit, they are too thick.
Could it be that the 650 break disk is thicker than the Z500? Does anyone know?
I really need new brake pads, just hope I can find some that fits... They take up about 2mm too much space to be able to put the brake caliper back in place.. and the piston in the brake caliper is pushed back (I needed to change brake fluids anyway, so the system is dry at the moment).

The single front disc models did have thicker rotors, either that or someone has swapped a rear to a front...

The 270mm 7 spoke wheel discs are pretty common among lots of kawi fours of that era, although some are 260 or 280mm. Service limit is 4.5mm i think, the rears are about 6.0 mm.

The later 81 GPz550 twinshock has a different fork spacing from most of the others whilst using apparently similar components, not sure about the z500.

I am not at all sure of the diameter of the rear disc, but the thickness is most likely 6mm (have not measured, but it's thicker than the front discs).

This is a two disc front wheel and one disc back wheel.

I never got to try changing the pads for the front discs, I gave up when I had been working long enough on the rear disc and had to return home from dinner.
Might be that the pads would work on the front discs, but have to try that first.