NX250 brake caliper maintenance

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scrambler
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Beiträge: 8199
Registriert: Fr Sep 14, 2012 8:50 am

NX250 brake caliper maintenance

Beitrag von scrambler »

Disclaimer
If you have never worked on the brakes before, a knowledgeable friend should help you


The Nissin calipers used in our NX250 and many other Honda dirt bikes with 240mm brake discs (e.g. XL600R, some XR250, XR600) have a tendency to jam. Dirt gets behind the outer dust seals and the pistons then go back more and more difficult. In addition, a hard coating forms on the pistons, which damages the dust seals when the pistons are pushed back. When changing the brake pads you should clean the pistons before they are pushed in.

To do this, press out one piston at a time (usually only one will move anyway, otherwise secure one with a clamp) with the handbrake lever a bit (not too much or the piston will fall out) and clean it with some brake cleaner and for instance with pipe cleaners https://www.amazon.com/Smoking-Cleaners ... P6Z1NT2YQS.

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When the piston is clean, a bit silicone brake lubricant (seal kits often include that pink or orange stuff https://www.ebay.com/itm/2FastMoto-Fron ... SwmtJXUI5G) can be applied to reduce the friction of the dust seal. The clean piston now only has to be pushed back with finger force. If you need a clamp, the dust seal is very likely already damaged and must be replaced.
The clean piston is secured with a screw clamp, then the other piston can be pushed out and cleaned.

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During the entire process, the fluid level in the brake cylinder reservoir should be monitored. Suck brake fluid from the reservoir with a syringe before it overflows.The level should also not fall below minium, otherwise air could be forced into the brake line. And after changing the brake pads you should also change the brake fluid.

The two sliding pins of the brake caliper need a little grease (preferably special heat-resistant grease for brake callipers) so that the brake runs smoothly again. And the screw pin and the cover cap should get some anti-seize lube ceramic paste and the tightening torque should be observed. Otherwise it will be very hard to remove the pin / cap the next time when changing the brake pads. Many brake calipers were ruined because pin /cap could not be removed.

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scrambler
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Beiträge: 8199
Registriert: Fr Sep 14, 2012 8:50 am

Re: NX250 brake caliper maintenance

Beitrag von scrambler »

If after the cleaning the brake is still jamming this is mostly due to dirt in the grooves of the dust seals. In some cases the dust seals are push outwards, jamming the pistons.

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Then it is necessary to push out the pistons to clean the groves of the dust seals.

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Sometimes the jamming damages the housing of the calliper.

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Then you need a replacement caliper. NX250 calipers are rare and hard to find. Luckily, that caliper (27mm piston) was used in most XR and CR dirt bikes from 1988 onward, for instance XR250, XR400 or XR600. The XR650L fits too, but because of the large XR650 brake disc you have to use the NX250 caliper bracket.

There are chinese replicas of these Nissin brakes https://www.ebay.de/itm/262721170229?ep ... %3A2334524, but I have no idea if they really fit or if the quality is decent enough to bet my life on that.

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BurningStar
Beiträge: 78
Registriert: Di Feb 26, 2019 8:41 pm

Re: NX250 brake caliper maintenance

Beitrag von BurningStar »

Suzuki RMZ Caliper will also fit.
It's the same Nissin 27 from the XR 650 l Version.

So on there are a few Caliper from BERINGER for The XR 650 l and the RMZ, If someone have too much money...
NXR 250 R. - MD 16-30
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