Brake pistons/ Vmax forks

[Sanders]

Now that I figured out exactely what model I have, I'll elaborate on my problem. The main problem I have is that the calipers in the front and back were frozen stiff. When removed the pistons are corroded and most likely beyond repair.

While digging for the parts I came across partsnmore and they have brake piston for 78-81 xs1100's. Now, maybe I'm over thinking this but do these fit on a 1979 xs1100 special. Looking at the part it looks like the piston I removed from my bike. Here's the link:

https://www.partsnmore.com/cat_index...tegory=chassis

Also, has anyone ever given any thought to putting a older vmax front end on an xs11. I'm asking this because I have Vmax shocks on the rear so it got me wondering about the front. Thanks

[Ken Talbot]

Yamaha made two different pistons. One fits only the front calipers on Specials. The other fits the rear caliper on a Special and both front and rear on Standards. Unfortunately, the ones at partsnmore will not fit your Special front calipers.

The good news part of the answer is you can probably clean up the ones you have. Thay may look bad, but there is a good chance any rust you see on the pistons will turn out to be outside of the part of the piston that actually rubs against the sealing o-ring. Take your time, and use compressed air or grease to free the pistons if they are stuck (use the search button to find lots of posts on these techniques). In fact, do a bit more reading first to see what kind of special long-nosed circlip pliers you will need, where the circlip is, and how everything will come apart and go back together. Calipers is a great starting place for building up some confidence for working on these bikes.

[Sanders]

That's what I thought. The pistons will have to be salvaged then. Thanks

[Sanders]

I have been giving some more thought to the Vmax forks on the xs special. The forks on the xs are 37mm and early Vmax forks are 40mm and in 93 they switched to 43mm on the max.

Would too much structural integrity be lost if the the triple trees were milled to accept the 40 mm forks, milling to the 43mm might be too much. I'm trying to figure out better options for brakes, wheels etc. Doesn't seem to be any shortage of Vmax parts. This also seems to be a more ecomonical option.

Any thoughts....

[The Lorax]

can you use the V-Max trees as well? I don't know what would be required to fit them to an XS but it might be a viable option without the loss of structural integrity. Just a thought, have a nice day and ride safe

[rodwerx]

Vmax tree

The first generation Vmax uses the same bearings for the triple tree.

[jwhughes3]

Since the XS650 uses the same pads as the 1100 though different calipers, are the rotors the same?

I was looking at pistons on MikesXS.net and wondering about interchangeability.

John

[WMarshy]

The first generation Vmax uses the same bearings for the triple tree.

There are members who have used FJ forks but it takes some modification to tge FJ trees to fit the XS. I havent heard anyone using the vmax forks and I'm not positive ther is or is not enough material to accept the 40 mm vmax tubes. Its not all that much material removal then ya think about it, I bet it would work... let us know if you try it. You could get a cheap set of upper and lower trees off ebay or on our site to try it on. I think you might run into problems fitting the tire between the lower tubes..?

[daveyg]

Might want to be careful pairing up forks with diff model trees, as others have pointed out in other threads you might get screwy trail problems, but it may work with std trees, if the vmax forks place the axle in the centerline of the fork. And going from 37 to 40mm is only 1.5mm increase radially, which isn't much (approx .059") if you want to try it, I will give you a good price on the machine work...

[Schming]

Since the XS650 uses the same pads as the 1100 though different calipers, are the rotors the same?

I was looking at pistons on MikesXS.net and wondering about interchangeability.

John

Yes, the disc rotors of the XS 650 are the same as the XS11