1981 Yamaha xs 400 special 2 front brake

Discussion in 'Motorbike Technical Discussion' started by zoot, Feb 21, 2008.

  1. zoot

    zoot Guest

    when i got my 400 the front wheel and carbs were in the basket. I
    think I got the carbs back together but I'm having trouble what parts
    come out of the basket and go on the front wheel. The books suck and
    the parts fisk don't tell me what some things are made of. I have two
    pairs of felt washers of different thicknesses and have a suspicion
    where they go [drum break] but only kinda sorta. does anybody know
    this stuff? HELLLP!!!
    zoot, Feb 21, 2008
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  2. zoot

    . Guest

    The felt washers probably have nothing to do with the brake or axle or
    the speedo drive as mechanical spacers.

    The only thing I can imagine they would do is act as a dust seal.

    Buy maybe they are foreign parts that somehow wound up in the box with
    everything else.
    ., Feb 21, 2008
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  3. zoot

    zoot Guest

    motogrid, yamaha 1981 xs400h front wheel, could parts 11 and 12 be
    made of felt? has anybody assembled this wheel from that vintage?
    zoot, Feb 22, 2008
  4. zoot

    . Guest

    #11 is a shim that would be made of steel. #12 is an oil seal that
    would be steel covered with rubber.
    I have assembled many wheels from that era and have never seen a felt
    washer in any of them.

    Like I said, it's possible that the washers are extra parts from some
    other machine.
    ., Feb 22, 2008
  5. zoot

    paul c Guest

    Others here may know this bike whereas I don't so I can't answer the
    specific question but I do know that some drum brake assemblies have a
    felt washer that goes around the brake cam immediately on the outside of
    the drum and the service manuals will say to coat the felt with oil when
    assembling. I guess some designs need it more than others to help keep
    road dust and moisture out of the drum. But the parts manuals sometimes
    call it a seal, not a washer, eg:


    (see part number 20 from the rear wheel, doesn't seem the same bike as
    the front wheel on this one would seem to have a disc.)

    On the other hand, maybe those felt washers are meant to go on the floor
    - I've seen a few there after watching people put hubs back together!
    paul c, Feb 22, 2008
  6. zoot

    zoot Guest

    Not the answer I was hoping for but the one I need to hear. Guess
    it's time to order everything I have doubts about. Thanx.
    zoot, Feb 22, 2008
  7. zoot

    paul c Guest

    Hey Zoot, if you do order the parts, will you post back here as to what
    that seal is made of? (#11 in steel makes sense, eg., one wouldn't want
    oil-coated felt inside the drum but #12 could be felt - I'd think rubber
    might bind, but I admit I'm just guessing. It's the fiddly little bits
    that always seem to take more time deciphering than the bigger,
    seemingly more important parts!)
    paul c, Feb 22, 2008
  8. Yes, they're dust seals that fit around the pivot arm. That said, the
    XS400 twins we got had disc front brakes. Did they do a drum version for
    the US? They did a drum braked 250 in the UK, but it was very rare.
    The Older Gentleman, Feb 24, 2008
  9. I, on the other hand, have assembled many wheels from that era too, and
    seen lots of them. In a recess in the brake plate, encircling the drum
    brake pivot arm.

    They're easy to overlook, so either you didn't see 'em or you haven't
    faffed with as many drum brakes as you claim.
    The Older Gentleman, Feb 24, 2008
  10. zoot

    Hank Guest

    Early xs400's here in Canada had a drum ft. (I'm kinda watching for one) I
    don't think as late as '81 though. OTOH the "specials" usually were trying
    to look like an earlier model with wire spokes etc. I have seen a lot of
    felt dust seals used on brake cams, mostly on rr wheels or ATV's..........
    Try looking up an earlier xs, it may be a frankenbike.

    btw Krusty actually calmly admitted he was wrong (!) in an earlier
    discussion about brake cams, a weakness in his vast knowledge?

    Hank, Feb 27, 2008
  11. I have an 81' xs400h and its a drum brake on it front and rear but it is a little more rare than the disc and drum model. I get offers from people allthe time wanting to buy it and I couldn't figure out why at first till I did more research to find out why.
    brandonshane311, Apr 5, 2014
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