Brake rotor identification

[Halloweenie]

Can anyone identify this brake rotor? Mine pulses rather too much, and I wish to replace it ASAP. My problem is I am on a student's budget, hence my looking for a deal. The seller states that it came from an '82 XS650, but I cannot find any pictures of one with one of these installed.

http://tiny.cc/6pqiz

Thanks a million!

 

[Capt_Zoom]

I don't think its stock...Stock don't usually have the venting holes. Might be an EBC or something...check what the aftermarket one's look like on Dennis kirks website. The depth of the offset doesn't look right to me either.

 

[weekendrider]

82-83 XV750? The spiral ribs matched the mag design? Home drilled?

 

[Halloweenie]

I think you might have hit the nail on the head. Thanks for the help.

 

[XSLeo]

It may have come off an XS650. most of the parts you find on Ebay are from bike breakers. They don't know much about bikes, just break them down and sell parts. It should work ok on yours if it is a later model with the single piston caliper.
Have you looked through the for sale section in the classified on this site yet.
Leo

 

[Grinder]

I have a nice rotor off of a 78 XS. $20 plus shipping. PM me if you are interested.

 

[gggGary]

Yeah some newer Yamaha rotor that has been drilled. Ask the seller to measure the OD to be sure. I would use it on an XS650 Some XS1100 special rotors are slotted and are XS650 bolt on.

 

[gggGary]

OK I reread the OP, why are you sure it's the rotor? Have you tested rounout? Has the caliper been apart? I would be more suspicious of a sticky piston or the like in the caliper. Just thinkin' out loud.

 

[littlebill31]

To add to Gary. Did you make sure the pads are in correctly and that the pad retaining screw is installed/tight?

 

[oldbiker]

hi ,,,i think that it is only a later rotor ,,,,buttttt somebody has drilled a pattern in the disc ,,as all xs650 discs were solid,,,, earlier discs bolt together,,, regards oldbiker

 

[Halloweenie]

OK I reread the OP, why are you sure it's the rotor? Have you tested rounout? Has the caliper been apart? I would be more suspicious of a sticky piston or the like in the caliper. Just thinkin' out loud.

I actually took a micrometer to the rotor, and there is up to 0.15mm variance in the thickness of the disc between where it is sticking and where it is free. I checked the piston, it looks good, and the pads as well as the screw seem to be in working order and installed properly.

Is the variance in thickness common and I am not seeing the true problem?

 

[XSLeo]

gggGary the xs750, xs850 and the xs1100 Specials used the leading axle forks. These bikes used a different caliper and a smaller disc. They were the same size as the XS650 rear disc. The standard versions of those bikes used the same calipers and rotors as our XS650's.
Some were slotted. I have two sets of slotted rotors that the seller claimed came off XS1100's one set is 7 mm thick like ours and one set is 5 mm thick.
Leo

 

[gggGary]

I don't have manual handy for thickness variation specs, some car specs came in around .25mm so you are getting there. .15mm =6 ten thousandths or .0006"
Leo I am with you on the XS750 850 specials being smaller but I think the 1100 special uses the bigger rotor like the XS650. It may be thinner than the standard XS1100 but I would be good with that.....

From an ebay EBS rotor ad
EBC PRO-LITE FRONT BRAKE ROTORS YAMAHA XS1100 ALL

[FONT=Arial, Helvetica, sans-serif]

EBC PRO-LITE FRONT BRAKE ROTORS​

1981 YAMAHA XS1100 LH Midnight Special, 1980 XS1100 LG Midnight Special Left/Right, 1979-1981 XS1100 SG/SH Left/Right, 1979-1981 XS1100 E/F/G/H
​

[/FONT]

 

[highspeedhamish]

Early 80s XV Virago Series Rotor possibly from a 500cc version.

Picture for reference. The rotor has been drilled though..

 

[Halloweenie]

Well call me stupid. Thinking I may have missed something last time, I tore down the caliper again. This time,however, I dropped it due to my hand tremor. I would not have believed it if I hadn't seen it myself; a small piece of gravel fell out of somewhere. Now my wheel spins quite freely, but I can still hear where the disc is slightly thicker. Thanks for the help all.

 

[gggGary]

Ride it and see how it works?