XS11 brake rotor compatibility

[jpmoregone]

Does anybody know if rotors from any other bikes will fit a 1981 XS 1100 H? I'm having trouble finding straight ones with any meat left on 'em, locally or on eBay, that are specifically for the XS11.

[Ken Talbot]

The front rotor from an '81 XJ650 is a direct swap. I'm guessing Yamaha didn't make too many different rotors between 1978 and 1981. Look for any just about any model in this year range...

[sixtysix]

Well it depend on what you mean by direct swap. The 78-79XS all had non-slotted rotors, in 80 the standard had non-slotted, and the specials had slots (which now means they are directional) and have to be fitted on the same side they came off. So while they will fit, they are not the same. Every bike I have seen the rear rotor is worn, never buy a used rear! The fronts are usually a lot better. (and can be used on the rear, but only on the same side for specials).

Here is a letter Jerry Fields wrote on the subject:

From: Jerry Fields <jerryfields@mac.com>
Date: Thu Apr 11, 2002 11:28 pm
Subject: Re: [xs11] warped front rotors

Solid rotors from earlier XSs will bolt right up. So will rotors from a
same-era 750 Seca. New rotors, EBC brand, go for about $175.00 each through Zanotti Motors.

Spec on the rotors is quite narrow when it comes to having them machined,only about .006 deflection (15 mm run out) and minimum thickness is .26 in or 6.5 mm. Gives you very little room to play with, considering you will have to get both sides of the rotor worked on.

You might try finding a local machine shop that is equipped with a surface grinder. I had a pair of rotors machined for $45.00 this way, but had to wait a few days until they worked the job in. (Rotors were solid from a '78 standard.)

Last option is to go with the 'floating' rotors sold by Merriam Cycle. Think they were in the $200.00 range.

Jerry Fields

Here is an answer I gave on the old list along with a link to EBC:

Another way to do it is go to
http://www.ebc-brakes.com/Applicatio...ese/yamaha.htm
and see what the part number for the XS is and find out what other bikes use the same one. Fronts should be changed in pairs since 'one that fits' may have slots or other things that may make it look or act slightly different.

Here is what is shows for fronts
Left MD2024LS
Right MD2024RS

A quick scan reveals these other Yamaha bikes with those same rotors:

82 XJ 1100 J, (all) XS 1100, 80-81 XS 850 LG/LH/SG/SH, 77-79 XS 650 D/E/F/2F (left side front only), 81 XJ 650 LH Midnight (left side front only), 76-78 XS 500 C/D/E

Remember this cross referece on works for the same physical size rotor and it will work (but may be slotted or not, or have a different spoke pattern or something.

[sixtysix]

Well crap the EBC site is moving and has no application data up right now, here is what they list as places to check in the US:

For Motorcycle parts in the USA www.midwestactioncycle.com or www.brakesrus.com

[jpmoregone]

Hey, I really appreciate it. You've given me a lot more information than I thought I'd get. This helps a bunch. Later.

[Robert Haller]

Originally posted by sixtysix
Every bike I have seen the rear rotor is worn, never buy a used rear! The fronts are usually a lot better. (and can be used on the rear, but only on the same side for specials).

My bike was like that. Is it because people use the rear brake more that the fronts? You should be able to use left or right front rotors for the rear on specials as long as they are solid, I have with no ill effects.