Neighborhood kid got a KX125....brake lever is HARD to pull

Title describes it.

 

Kid just brought it over "Mr. Coo, can I try my new bike on your track?"

"Sure Matt, bring it over."

 

Looks good.  One fork is weeping a bit.  He is timid on it coming off a CRF110 (or something like that).

I tried it.  Seems to run alright. 

But man-o-man, front brake sucks.  SUPER hard to pull.  Like whole hand it and can't get the front tire to skid.  It works, but not that much.

 

My 250 and my boy's 85 are single finger action....like these bikes should be.

 

So, of course, Matt asked me to look at it (his dad did).  The kid doesn't know the front brake sucks so bad as has not riden it much yet.  Certainly not got on it enough to need a bunch of stopping power.

 

So, what should I look for?

Wondering if the problem is on the bars: master cylinder or maybe even lever action binding.  Or maybe the caliper?

 

It's not like the pads or something aren't gripping....can't even pull the lever in.

 

I'll let ya know what I find when I start tearing into it.  Just wondering if there is something specific to look for first.

 

Not sure what year it is...2000 or so?

 

CooHead

How well has it been taken care of? First thing I would do would be lube the cable, not gonna hurt anything and might save you some time, and it's a good starting point.

I would first start by flushing the system of old fluid and put in fresh brake oil,also,as you mentioned ,the lever may be over-tightened to cause it to pinch,which would be a quick fix. If the line wont respond to flushing that could also be the problem and need replacing.Does the wheel spin freely by hand ?

Good points to look at first.

He is bringing it over today so it's here for a ride day tomorrow (his parents wont be around tomorrow).

 

I'll give it the once over and check there quick simple items first.

Brake fluid is non compressible, and as such may narrow it down to just the moving parts. I bought a 99 125 and the front brake was seized up much as you describe. It turned out to be a stuck piston.

Make sure it's got the right lever on it.

if one of the fork seal's is leaking you may have fork oil on the disc and pads?

hi ledger :p

Edited by smezmx

if one of the fork seal's is leaking you may have fork oil on the disc and pads?

hi ledger :p

Hello "OH GREAT MX ARTIST JOHN" !!! :worthy:  :p

Brake fluid is non compressible, and as such may narrow it down to just the moving parts. I bought a 99 125 and the front brake was seized up much as you describe. It turned out to be a stuck piston.

Yeah I'm with this guy.

pop the mc cap off.   stuff could have sat so long that the brake fluid turned into a crystal like gel.  had that happen on an old rm. brakes still kind of worked but they did what you said never locked up or really worked well at all

It is expensive and requires a lot of precleaning prior to use but I run dot 5 break fluid. I won't use dot 3 or 4 due to moisture soak. And dot 5 has a better pressure build over conventional break fluid.

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