Brake issues

hassbeen
I have a YZ250F 2014 model. The bike has 30 hours on it. The front brake is spongy and too soft.
I have stripped it down completely, replaced the master cylinder seals with a new kit. However it remains very spongy. I have sucked out the air from the brake fluid prior to replenishing it and bleed the brakes properly. I have never experienced anything like this. There is no leak on the brake line or seals on the calipers.
Any ideas?
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drumheller34 7/5/2016 10:22am
7/5/2016 10:22am
Sounds like your brake line is "ballooning". I would go with a stainless steel brake line. It will help a good bit but the yz brakes are weak. Maybe an over sized rotor
CarlinoJoeVideo
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CarlinoJoeVideo 7/5/2016 10:45am
7/5/2016 10:45am
Try the new brake line or keep bleeding.

You can also take the cap off the master cylinder and zip ty your lever to the bar, leave this overnight and it helps let the air bubble float out.
hassbeen 7/5/2016 10:42pm
7/5/2016 10:42pm
Thanks guys, I have an oversized rotor. Going to go for the steel braided line next. The zip ty on the lever certainly helped a bit too.
IceMan446
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IceMan446 7/7/2016 10:50pm
7/7/2016 10:50pm
Going to sound weird but I had the same issue and changed out the copper washers on the banjo bolts and re-torqued them and it helped big time.

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hassbeen 7/8/2016 6:35am
7/8/2016 6:35am
Might be an option. easy fix.
FGR01
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FGR01 7/8/2016 12:56pm
7/8/2016 12:56pm
IceMan446 wrote:
Going to sound weird but I had the same issue and changed out the copper washers on the banjo bolts and re-torqued them and it helped...
Going to sound weird but I had the same issue and changed out the copper washers on the banjo bolts and re-torqued them and it helped big time.
If you think about it, it probably was not the new washers that helped but the fact that you had to re-bleed the brakes after removing the banjo bolts and line.
SOAB_465 7/14/2016 10:59am
7/14/2016 10:59am
I had the same problem on an '11 YZ250. It turned out the fork lug was a tiny bit bent, and the caliper wasn't lining up with the rotor squarely, so the rotor was flexing and making the lever spongy.

I ended up filing a few thousandths off of the top caliper mount on the fork to re-true the caliper carrier, and now the brakes are perfect again.

It's tough to notice but, if the rotor is moving AT ALL when you pull the brake, the caliper is bound up or out of alignment somewhere.
panic_rev_214 7/14/2016 12:29pm
7/14/2016 12:29pm
I HAD HERD THAT BRAKE HAS HAD ISSUES WITH HIS SHOLDER COLLER BONE BROKEN
hassbeen 7/15/2016 1:47am
7/15/2016 1:47am
SOAB_465 wrote:
I had the same problem on an '11 YZ250. It turned out the fork lug was a tiny bit bent, and the caliper wasn't lining up...
I had the same problem on an '11 YZ250. It turned out the fork lug was a tiny bit bent, and the caliper wasn't lining up with the rotor squarely, so the rotor was flexing and making the lever spongy.

I ended up filing a few thousandths off of the top caliper mount on the fork to re-true the caliper carrier, and now the brakes are perfect again.

It's tough to notice but, if the rotor is moving AT ALL when you pull the brake, the caliper is bound up or out of alignment somewhere.
good point, I'll check it.

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