Brake Disc Turning?

[Snow]

Is it possible to get XS11 discs "turned" like car discs and if so, can a normal parts store that turns car discs turn XS discs?

Forgive me if this question has already been asked, I didn't find anything through the search function.

Pete

[Jerry]

Brake rotors on a motorcycle are a different alloy than auto rotors and brake drums. You will find very few shops equipped to turn MC rotors. Some machine shops, equipped with a large surface grinder, can grind them flat if they are not to badly damaged. However, you will pay shop time. I had one set done this way and the cost was $45.00.

The tolerance for thickness on the rotors is quite small, about .004 inches. This means you remove only .002 per side, almost nothing. If your rotors are warped, best off replacing them. All XS/XJ front rotors are interchangeable, though the XJ and some '81 XSs have slotted rotors that are directional...left and right sides should not be interchanged due to the direction of the slots. Rotors are stamped "L" and "R". However, the size, offset, and bolt patterns are identical. I used a set of solid rotors on my XJ for a while until I located another slotted set. Rear rotors I am not clear on...have heard they are the same as front for the XS, but do have a diffrerent part number for the XJ. Hopefully someone else can verify this.

Other Yamahas of the same era used the same rotors; I am thinking the 750 Seca ones are interchangeable, and there may be others.

New rotors are in the $200 range, so it is worth the time to try and find used rotors if yous are getting bad.

[Snow]

I don't think the rotors are incredibly bad off, but I am getting a good amount of pulsing (with fairly fresh pads even) that is starting to give me problems stopping safely. I think that when I get my new SS brake lines (Thanks Chris) it might be an even bigger problem than now.

Back to the salvage yard to pick apart that XJ again. Thanks for the info. Btw, is there a good way to tell the condition of rotors while they are still at the yard?

[sixtysix]

DO NOT BUY A REAR ROTOR without checking with a dial caliper, most are worn beyond the limit.

[Snow]

Thanks for the warning sixtysix - luckily only the front rotors seem to have problems on my bike.

[Jerry]

If possilbe, take a piece of glass bigger than the rotor. Place the rotor on the glass and see if ou can slip the corner of a piece of paper under the rotor at any point. If you can, might want to pass up that particular rotor....

Let us know what you paid for the rotors if you find a set. I was quoted anywhere from $35.00 per set up to $50.00 each, finally paid about $50.00 for a set in very good shape.

[squarehdca]

I have turned most stainless bike rotors on my lathe . The other guys are right in that the tolerances are tight and the rotors are so thin to begin with ( less weight) that they are prone to warping. Car disc brakes are cast and much thicker.
I clean them up with a carbide postive rake tool ; then have to finish grind with a toolpost grinder . Unless you cant find new parts , it's probably cheaper to buy replacements .
Ed Q.