TOPIC:

I bought a pair of drilled front disks for my Z1. Looked great, been surface milled but when I put them on the bike I got a pulsing in my lever. After running them for a few miles, I could see a blueing in some spots where the drilling is. The run out seems good and when I ask about turning them, no one wants to touch them.
Question
1 Could it be I'm using organic pads when I should be using cintered?
2 Should the holes be chanfered?
I bought a third from ebay also but it is well worn and very close to the limit.
I'm back to my solid disks and they are almost twice the weight. I could have them drilled but the unsprung weight is what I was going for plus the advantage of drilled disks.
Any suggestions?
Steve

pictures? any shop that does flywheels should be able to check/surface them

These folks specialize in resurfacing bike rotors. Ed

www.truedisk.net/

Was that a eBay ad above your post? If not someone should buy it. That's a vintage Vetter fairing (forget the name) on it. The KZ 900 has parts compatible with all the years. The wheels are vintage ABE mags. Com'on guys one of us Z heads have to be able to buy it for $2500. As for the stock Z's, that's why I kept all my old parts. The cut up ones are going for a song.
Steve

When I get back home I'll take some pic's and put them up.
Thanks
Steve

Are the shims installed correctly?

You checked the run out, was this with discs fitted? If the lever is pulsing then one or both of the discs is warped. Was the disc mounting flange cleaned up?
Removing and blocking one caliper at a time and using a dealers brake testing machine, or even a careful roadtest will show you which rotor is bad. The blueing in certain areas could be a clue.

Sintered pads wear the discs quicker but give better wet braking I think. Drilling imporoves wet braking and cooling.

Refacing rotors is possible but you need to allow some 'meat' over the service limit thickness.

I've noticed a lot of ebay breakers don't specify whether used discs are flat or even measure the thickness.

Lighter discs reduces unsprung weight and the polar moment of inertia, but I don't know whether you'd actually notice the it on the road.

I made my own clamp and checked the run out. Checks good. In the past I've had a slightly warped disk but the pulsing wasn't like this. I think the drilling happened after the grinding. Maybe a clean up is in order. Plenty of meat left.
Thanks for the input.
Steve

peter1958 wrote: Are the shims installed correctly?

No shims. You might have something there. The calipers might be too close. I didn't center them. They work with the solid but the drilled ones are thinner than the stock ones. If you notice from my pic, they are from a H 2. I liked them because of the cooling Finns and they are beefier. That's why I was looking at unsprung weight. With the old style front end, anything would be a improvement.
Steve

One or both disks are warped. It is not going to be the calipers or the pads.