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1988 CBR 250 R (J) Brake Piston Fitment

Discussion in 'Technical and Troubleshooting Torque' started by Sloth, Oct 31, 2007.

  1. Hello,

    I decided to fit braided lines to Mrs Sloths bike and give the calipers a thorough service since she thought the brakes were a little shabby.

    Having stripped the front caliper I found something a little odd. The pistons are sat in the caliper such that the "closed end" of the piston faces the back of the brake pad. Every other caliper I've seen has been the reverse of this with the "open end" facing the brake pad.

    Its a floating nissin 2-pot and the cbr 250 service manual (despite having an addendum for the J model) only shows the cbr 250 rr caliper which is a different model (different shape completely), so no help there.

    So I don't know if its correct or if its prior service was carried out by a retard. :?

    The brakes are soft and I'm starting to wonder if thats not because there's probably an air bubble sat behind each piston.

    So has anyone worked on a cbr 250r (j) caliper before and can let me know if this is normal? Seems contrary to everything I've seen before (or seen in manuals for that matter).....

  2. Do you have the part number for the caliper piston? If so, type it into the parts finder on this site http://www.bike-parts.fr/recherche_piece.php & it will give you a nice exploded parts diagram & also tell you what other Honda bikes the part is common to. Hope this helps. Cheers
  3. Thanks for the reply roarin. Looks like a useful site for my 9' but doesn't have the fiche for the two-fiddy unfortunately. I did find a place in the uk which has a piston kit:

    MC19 Brake Piston Kit

    The end shown in the pic is what I see against the brake pad. Maybe the different material is used to dissipate/isolate heat :-k

    Anyways - I'll get some seals on back order and pop the pistons out and see what I find..... worst case maybe I'll wander around sumoto and persuade them to pop out some pads on the pretext of checking them, so I can get a shufty into the caliper to see how they are on other bikes :grin: