KZ1000 Front Disc/Rotor Thickness

Can amyone tell me what thickness the OE discs/rotors were please for the following models, they all used the same disc.

Drilled/Ventilated
KZ1000-A3 (KZ1000) (1979)
KZ1000-A3A (KZ1000) (1979)
KZ1000-A4 (KZ1000) (1980)
KZ1000-B3 (KZ1000 LTD) (1979)
KZ1000-B4 (LTD) (1980)
KZ1000-C2 (Police 1000) (1979)
KZ1000-C3 (Police 1000) (1980)
KZ1000-C4 (Police 1000) (1981)
KZ1000-D3 (Z1R) (1980)
KZ1000-G1 (Classic) (1980)
KZ650-E1 (LTD) (1980)
KZ650-F1 (1980)
KZ750-G1 (LTD II) (1980)


Non - Drilled (same disc with no holes
KZ1000-B1 (KZ1000 LTD) (1977)
KZ1000-B2 (KZ1000 LTD) (1978)
KZ1000-C1 (Police 1000) (1978)
KZ1000-C1A (Police 1000) (1978)
KZ900-B1 (LTD) (1976)

Big Bikes use 7mm rotors, with a 6mm minimum.
Some smaller KZ's use 5mm rotors

Big Bikes use 7mm rotors, with a 6mm minimum.
Some smaller KZ's use 5mm rotors

Are you sure? Yhe KZ1000 rotors/discs i have say 'MIN 4.5mm' on the back, they're the ones i need the original thickness of. My Discs are ok but are slightly uneven on the rear face. I have the single disc off a 1977 KZ750 Twin & a 1977 KZ650 (both the same disc), they measure near 7mm wide with v little wear. I was going to get each disc machined down to match the spec OE thickness of the discs i posted in my 1st post here, i'd have discs as good as new then.


So did the 'Min 4.5mm' Discs start life at 5mm?? Thats all i really need to know.

Single disk front brakes use a 7mm rotor, dual disk front brakes use a 5mm rotor.

Steell wrote: "Single disk front brakes use a 7mm rotor, dual disk front brakes use a 5mm rotor. "

That's exactly what my KZ650 manuals show:

KZ650 B models – single front - effective diameter = 250mm; thickness = 6.9 - 7.1mm; Limit = 6mm; rear brake = drum

KZ650 C and D models – dual front - effective diameter = 231mm; thickness = 4.9 - 5.1mm; Limit = 4.5mm; rear brake effective diameter = 237mm; thickness = 6.9 - 7.1mm; Limit = 6mm

Thank you very much guys.

Just been told by my local machine shop that he can't machine bike brake discs as they're made from 318 Stainless...........now i don't know if that means HE cant machine them or they cant be machined at all.

They can be done, but not using regular car brake equipment. It takes special grinding equipment. Here's a link to a place that does them:

www.truedisk.net/

Some nice info about the process there Ed, thanks. Shipping would make it a very costly option for me though. I'll see if anywhere else local can do it.

My CSR are 4mm front, 6mm rear.

Lots of rotors for different years though... and then there's aftermarket :pinch:

Best to just check with OEM. Or is might be stamped on the disc somewhere.

I thought the thickness was stamped on the rotor somewhere(?)

Minimum thickness is stamped on it, i'll go check here to make sure & report back in this post.