On the XS1100 rotors. They made two versions of the bikes. The Standard and a Special.
The standard used the same style of forks our XS650's use. The Axle was right on the bottom. The Special's used a different fork. The axle was on the front of the fork lower and up a few inches from the bottom. These are leading axle forks. They used a different caliper and rotor size.
The Same applies to the XS850 and XS750. I bought two sets of the slotted rotors. One set was from an XS1100. These were 7 mm thick. The other set was from some other bike. They were 5 mm thick. The 5 mm are on the 75. The 7 mm are on the 82.
There is about a 28% weight savings on going to the 5 mm rotors.
I learned these differences in the brakes the hard way. Bought the wrong parts because I didn't know better. I might recommend asking the seller to give you the rotor diameter before you buy.
Leo
Hi Leo,
BTDT.
FWIW the XS650/750/850/1100 WHEELS are identical and will swap between ANY XS 650/750/850/1100 bike.
Note that very early model XS1100 front wheels are more massive than the others but they'll still swap.
And any brake disk will bolt up to any wheel. Even the wire wheels.
What's different is the pre '77 XS650 disks are dished different and the XS750/850 disks are the same smaller diameter as an XS650 REAR disk.
So XS11 (Standard or Special, slotted or plain) brake disks will fit any XS650 but will only be compatible with a '77 or newer brake caliper.
So yeah, best to check the disk diameter before purchase. My son E-bought a brake disk & left side caliper to dual brake his XS650.
Caliper was perfect, Disk was too small. The parts musta been from an XS750/850 Standard.
Giving the seller the benefit of the doubt, perhaps he didn't know there was a difference either.