Replacing front brake rotors

[eroellig]

So, I finally had some time to swap out the warped front brake rotors on my SG today. Thought I'd "toss them on" & have a little time for a ride today before I do another 4 weeks of business travel.

I had the wheel off the bike from a few weeks earlier, so I got right to taking the old ones off & putting the new ones on. So far, so good.

BUT, then I went to put the wheel back on the bike, the two new rotors seem to be set in more narrowly than the old ones and will not fit in the slots on the forks.

I've seen numerous people say they've used the MikesXS rotors and this thread indicates that the xs650 is compatible with all models of XS11.
http://www.xs11.com/forum/showthread...ight=ebc+rotor

So, what am I missing?

[Ken Talbot]

Take the calipers and caliper mounts off first. Install the wheel, being sure to tighten the castellated nut to get the axle properly positioned to that fork leg. Put the caliper mounts back on. The caliper mount on the side with the castellated nut should fit on directly. The caliper mount on the other side will probably bind whan you first put it on. This is where you adjust that fork leg in or out, then hold it in place with the pinch bolts on the bottom of the fork leg. After that, the calipers shold be easy to put back on.

BTW - loosen off your forkbrace before you start any of this, and put it back on after all this.

[eroellig]

Take the calipers and caliper mounts off first. [...]

BTW - loosen off your forkbrace before you start any of this, and put it back on after all this.

Ken, Thanks for the reply. I had the calipers off already. However, my special doesn't have separate caliper mounts. They are cast as part of the lower fork. Didn't have the Tkat brace off. Getting rid of that helped a little. However, I still can't see how this will work. Here are a couple of pic's to show what I mean.









Still clueless......

[Montreux_Blue]

Can't you put some washers/ spacers between the disk and wheel where it bolts onto the wheel to bring it out?

[Ken Talbot]

Oops, sorry about the misdirect, Eric. You did say right at the start that you've got an SG, and I launched into the spiel about the front end of a Standard. They are as you note two quite different things.

I'll have a look at my Midnight in the daylight to see if I can make a bit more sense of it all.

[TopCatGr58]

A definite canundrum?

Hey Eric,

I did a bunch of research comparing the Yamaha part #'s for the rotors, but deleted it when I saw Ken's post, thinking that he had found the solution?

But after seeing your photos, it got me to thinking that perhaps the MIkesXS rotors are NOT so univerally usable as "WE" thought!?

The 650 rotors have the same part #'s as the 78-79 xs11 standards and specials, they are NOT slotted. Same # for the 80 standard. Regrettably Yamaha doesn't list part #'s for the 80 Special?? Then the 81 Special has a different prefix due to the change in design....slotted rotor.

I tried comparing the lower fork tubes just among the XS11's, and the 81 Special # IS different than the 79 Special !

SO.....it may be that somehow Yamaha changed the design of the Specials lower fork sliders during the year transition?

I looked in my EBC catalog at their rotor applications, and the # quoted in the 2002 thread(MD 2024 R&L) you provided were correct for the early model xs11's, and the 77-79 650 STANDARDS.

They(EBC) lists a different # for the 77-79 650 Specials(MD2025 R&L)!
They list yet another # for most of the 77-83 650's Standard/Specials(MD2023 R&L)?

The 2023 and 2024 are 298mm diameter whereas the 2025 is 266mm diameter.

Regrettably EBC doesn't list the offset values for these different discs, but I'm thinking that they are the same, it's just the diameter that's different!

79XS11F 1J3-25831-00-00 DISC, FRONT BRAKE SOLID
79XS650 1J3-25831-00-00 DISC, FRONT BRAKE

81XS11H/SH 3H5-25831-10-00 DISC, BRAKE SLOTTED
81XS650 1J3-25831-00-00 DISC, BRAKE

EBC OEM to EBC cross reference states for the
1J3=2024
3H5=2024

The EBC OEM to EBC cross reference lists the 2024 for both the early part # as well as the later slotted #.

So...after all of this, I can't understand why the MikesXS rotor would be different,flatter, less off set than the XS11? Mikes only lists the 1 model for ALL of their 650 applications!

SO....a simple fix would be as suggested, to get some 2mm thick flat washers and put them UNDER The rotors to position them outward hopefully enough to allow them to fit within the lower fork rotor guides!?

[Ken Talbot]

Eric, here's a couple of shots that do show a couple of minor differences:

On mine, the speedo drive looks like it is tighter to the fork leg. Then, it is hard to be sure from our two slightly different angles, but it also looks like the speedo drive sits a bit deeper into the hub. Be sure that the two little ears that drive the speedo unit are straight and that they engage without any binding or hang up.



On the other side, the collar on my bike definitely sites deeper into the hub. Your appears to be holding up on something.



I noticed that on my bike, the rotors clear the slot, but not by much more than 1 mm or so. Until you start inserting the axle, you can rotate the ends of the fork tubes to gain some clearance, then the axle locks everything into alignment.

HTH

[eroellig]

Eric, here's a couple of shots that do show a couple of minor differences:

On mine, the speedo drive looks like it is tighter to the fork leg. Then, it is hard to be sure from our two slightly different angles, but it also looks like the speedo drive sits a bit deeper into the hub. Be sure that the two little ears that drive the speedo unit are straight and that they engage without any binding or hang up.[...]
On the other side, the collar on my bike definitely sites deeper into the hub. Your appears to be holding up on something. [...]
HTH

Thanks for looking Ken. I'll take a look and see if I can see why my collar isn't seated as deep as yours is.

Eric