1. Having trouble logging in? Try closing your browser and re-opening it. If that doesn't work, try a different browser or device. The site will be updated soon to resolve these browser issues.
    Dismiss Notice
  2. Dismiss Notice
  3. Hey Facebook people... We've created a group for XS400.com members to connect. Check it out!
    Dismiss Notice
  4. Want an XS400.com t-shirt? Go to the store to order. Limited sizes and quantities available.
    Dismiss Notice

Front Brake Disc Swap Problem

Discussion in 'The Garage' started by Hasty, Sep 21, 2022.

  1. Hasty

    Hasty 1982 Maxim XS400

    29
    11
    3
    Ottawa
    My engine finally runs great thanks to the forum, but when I took the bike to get safetied, they told me my front rotor is too warped to pass. I haven't had any problems with it so it's a bit annoying, but can't fault the mechanic for being thorough I guess. Getting it replaced is now a time sensitive thing though because I don't want to have to pay for a second safety.

    So I happened to find a disc for sale in town from an XS650 that is the right diameter, right bolt holes, right offset, it's just a little thicker than my old disc. I collapsed the cylinder in a bit and everything fits fine with my current brake pads which have a fair bit of life left in them, BUT if I put in new pads, the inside pad (the side that is stationary and isn't actuated by the cylinder) sticks out too far and I can't get the disc in. Any ideas out there for how I can get the new pads installed? Is it totally insane to just grind down a fresh brake pad about halfway so it fits? Do I just need to get wider calipers or a thinner disc?

    Photos attached of the current partially worn pads with the new disc so you can see what kind of clearance I'm working with
     

    Attached Files:

    Last edited: Sep 21, 2022
  2. tstidham

    tstidham XS400 Enthusiast

    It does appear the xs400 and 650 share the same rotor according to parts diagrams. Maybe the issue is a stuck caliper slide pin or you have some debris inside the caliper holding the piston out. Use an old pad and a c-clamp and crank thepiston fully in or try to flush the caliper out with brake cleaner and compressed air after removing the banjo bolt and bleed screw. See if anything flies out.
     
  3. Hasty

    Hasty 1982 Maxim XS400

    29
    11
    3
    Ottawa
    Thanks tstidham, it did turn out the slide pin was just stuck. So I thought it was extended all the way out, but it had a bit more travel once I got it moving again. I think the rotors are different thicknesses because the one I got off the 650 was a rear disc. Maybe the front discs are the same between the 400 and 650? Either way, everything works now. Passed the safety, jumped through all the hoops to get the bike registered, just in time to put it away for the winter lol
     

Share This Page