Front Kz550 ltd disk brake

Hi guys!

I bought an '81 Kz 550 ltd a year ago, and I'm going through a resto/mod process with it and I can't find a right sized front disk. In the owner's manual they say single front disk have a minimum thickness of 6mm, but the disk on my bike reads minimum thickness 4.5mm.... It seems like i've look through the whole internet for the right disk and nothing and at this point I'm considering just going with a less used 4.5 mm disk. (This is the original disk part number from partzilla 41080-1127.)

Anyone knows where I can find the right disk? A used is okay as long as it's still within the minimal thickness range!

Merci beaucoup!

It would appear that someone put a disk from a dual disk front bake system on your bike, For the KZ650 models, the minimum thickness for dual disk rotors is 4.5mm; the minimum for single disk systems is 6mm. I suspect the KZ550 models have the same rotor thickness minimums. Ed

I think the reason the twin discs went thinner was just to keep the weight down, rotating mass on wheels is the worst place to carry weight: keeping unsprung weight and polar moment of inertia to a minimum is critical on sporty bikes.

The single disc 550 are less common, they all went to twin disc later on. The 7 spoke cast front wheels are on nearly all of the kz/twin shock GPz , The 270mm discs were fitted to a lot of different models. You might find a 270mm rear disc that will fit, they are all thicker than the twin fronts.

As long as whatever disc you use is not below the service limit I wouldn't worry about it.