CBR 400 brake problem

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  • #8950
    Marsha67
    Participant

    A nice project has just turned a bit sour. I have a CBR400 which has got pretty naff brakes. In a mad moment I set about them with a large hammer and I’ve cracked the caliper on the one side. Now they were never the best brakes in the world and I would like to put some better ones on there. Any ideas what would fit (from a breakers yard) and how I could improve the system in general. Do I need to upgrade the master cylinder if I fit twin-pot cylinders?

    Thanks in advance

    #19746
    GSX Rat
    Participant

    Easiest way is to drop the front end off and take the yokes to the breakers with you. You should then be able to find something with twin pots already attatched as well as the forks with mountings to suit. check em in your yokes to make sure they fit and hand over the folding stuff. You may get a deal on your old stuff as well depending on if you know the guy at the breakers/how generous he’s feeling. If the distance between the forks is incorrect for your yokes dont worry about it as you either get the spacer machined down, or another one made to adjust. As for the master cylinder, buy the one off the same bike you get the front end off.

    GSX750 Ratfighter / SR125 Rat / GSX600F / Beamish250 / Honda70 Rat

    Blackboard paint – Covers a multitude of sins!

    #19747
    Marsha67
    Participant

    Thanks for the quick reply. Are fork sizes usually the same across manufacturers or could I be a few mm out and still be able to clamp them up in my yokes?

    I presume I need the wheel too if it is another front end, so what problems could I have with different wheel sizes? Just trying to get my head round your suggestion GSX

    #19748
    GSX Rat
    Participant

    I suppose wheel and tyre size matters to a point, obviously a different size is going to affect handling etc. This may be important on a sports or other high performance bike but for a runaround it aint going to matter too much. If it concerns you then just look for a front end with the same size tyre/wheel. You may even get lucky and find that your existing wheel will fit if you choose something by the same manufacturer but a bigger capacity. As for fork sizes, you’ll have to take a set of calipers, or a rule whichever you have and measure them but the best bet is to take the yokes and try them. You may even find that the yokes from another model will have the same bearing sets and will fit. If the forks are bigger than your yokes, you could have some material cut out if you know anyone with a milling machine for the price of a pint, otherwise a quick work outside an engineering works with the guys going in should ensure a lunchtime job for about the same price.

    GSX750 Ratfighter / SR125 Rat / GSX600F / Beamish250 / Honda70 Rat

    Blackboard paint – Covers a multitude of sins!

    #19749
    wheelie
    Participant

    I’ve swapped forks across many makes and models. Only thing you must not do is force the clamp OPEN to get the new fork in. I’ve seen this happen many a time and they split, usually when you are riding the bike. Otherwise, be careful how much you get machined off the yoke to get it to fit, common sense usually tells you how far to go.
    Good luck



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