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How to bleed front brakes on kx125

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If it sat a while it's probably your piston in your master cylinder. Just get a rebuild kit. Unless u took the line apart to get air n it or ran out of fluid. If those two things didn't happen. Then it your piston

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If it sat a while it's probably your piston in your master cylinder. Just get a rebuild kit. Unless u took the line apart to get air n it or ran out of fluid. If those two things didn't happen. Then it your piston

It did sit over winter but it was work a month ago when I started and rode it. I have no school this week and was going to ride and can't really wait for the rebuilt kit.

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Squeeze the lever in and out a bunch of times then keep it n and reach down or have a friend back off the bleeder screw on the caliper. Fluid should squirt out with air. Repeat a few times. Remember when u back off the screw keep the lever n. Till u tighten the screw back up. If it doesn't build up pressure after the 3-4 time it's your piston

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I had a similar problem when I crashed on a steep hill and my bike ended up with the bike upside down attitude. It sucked just a little bit of air from the M/C and the lever came all the way to the bar with no feel. If tradional bleeding doesn't take care of it, and the M/C is good, make sure the M/C is full and then try pumping it several times, then zip-tie the lever all the way to the bar, and leave it overnight. Repeat again if you get some feel but it still isn't quite there. That normally takes care of the notoriously hard to bleed KX front brake IME.

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I had a similar problem when I crashed on a steep hill and my bike ended up with the bike upside down attitude. It sucked just a little bit of air from the M/C and the lever came all the way to the bar with no feel. If tradional bleeding doesn't take care of it, and the M/C is good, make sure the M/C is full and then try pumping it several times, then zip-tie the lever all the way to the bar, and leave it overnight. Repeat again if you get some feel but it still isn't quite there. That normally takes care of the notoriously hard to bleed KX front brake IME.

Hopefully it's not my mc I really was looking forward to ride today. But yeah it's not building any pressure but I was bleeding the brakes by myself so I was prolly doing it wron

When I did bleed the brake brake fluid did come out but no pressure

Edited by Drewster2020

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Hopefully it's not my mc I really was looking forward to ride today. But yeah it's not building any pressure but I was bleeding the brakes by myself so I was prolly doing it wron

When I did bleed the brake brake fluid did come out but no pressure

I had the replace my sons piston in his mc. It's a easy job. His was a. 2000 model. No aftermarket for that year but 01 and newer they have them and I believe there only 20 bucks for the hole kit

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Reverse bleed them.

 

Take the top off the reservoir, and suck all the fluid out with a syringe. 

 

Tap the brake line with a tool, starting at the bottom and working your way up to the top to loosen any stuck air bubbles. 

 

Grasp the rotor on both sides of the caliper with your hands, and put your thumbs against the caliper. Slowly press the caliper towards the rotor to depress the piston back into the caliper. Slowly, or you will take a brake fluid shower!

 

Keep pressing until the piston bottoms out.

 

Suction the rest of the fluid out of the reservoir, refill with new fluid, and pump up the brakes, being careful to keep enough fluid in the reservoir that you don't run out and get more air into the lines.

 


The reason reverse bleeding works is because the air wants to rise. Normal bleeding with the brake lever moves very little fluid per pump, not enough to move an air bubble all the way from the top of the brake line to the bleeder screw in one pump. So every time you release the lever, the bubble rises back up, and you never get any where. But with reverse bleeding, the natural tendency for the air to rise works with you, because you are also pumping the fluid up, and pushing the caliper piston in moves much more fluid than pumping the brake lever.

 

Of course after you get all of the air out, you should go through the standard bleeding procedure to completely replace all of the old fluid with fresh fluid.

 

If you still can't get any brake pressure the master cylinder needs new o-rings.

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