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sirthumpalot

rough front brake lever

8 posts in this topic

All,

I've noticed that if I pull in my front brake lever slowly that once the pressure builds that it seems to stick and sort of scrub (stick - slip - stick - slip, etc..) as I pull it in. I disassembeled, cleaned and regreased the lever and this helped some but the problem isn't all gone. Does anyone else notice this?

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Oh, I see that I need to rephrase the problem.

The brakes work fine, but while sitting still it is actually the lever which is rough. As I pull the lever towards the bar, it is the lever which is going a bit, then sticking, then going a bit, etc.. It's like if I add some force to the lever it doesn't move, then I add a bit more and suddenly it moves 2x as much as I wanted it to. Not quite that bad, but you get the idea.

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OK..that's clearer. Can you rule out that the slave cylinder plunger is not binding? Once that is elminated, I would carefully inspect the area inside the slot where the lever pivots. Is the pivot so worn that the lever sags as it goes through it's throw and rubs inside the slot? It doesn't sound like it should be all that difficult to find the source of the binding. If you put your ear next to the perch, can you hear any grinding noise as you squeeze the lever?

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Thanks for the replies. I completely disassembeled the lever, cleaned and re-greased it and that helped a bit, but the problem is still there. The bike has probably less than 20 hours on it so I don't think it's worn out yet. I think that it is the lever rubbing on the piston as it rotates. There were some rough spots on the lever at that point which I sanded and that helped a bit, there seems to be something stuck on the piston too so next I'll lightly sand that off and see if that fixes it. Not sure what it is that's on there..??..

I'm still very curious to know if anyone else has experienced this before.

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Well, I know what it is now. I sanded the top of the brake piston (where the lever touches it) and then cleaned it up and regreased it and the problem was 100% gone. So I gave the lever about 100 good firm pulls. After some wicked arm pump (without even leving the garage :) ) the problem started to come back a little bit, but only about 10% of what it was before. Maybe I will try a different type of grease and see if that helps.. Oh well, thanks for the ideas!

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I don't have a 426, but read all the tech information about motocross I can get. My kx had the same problem. The lever felt real grabby. I notice the area where the lever contacts the master cylinder (the top part) developed wavy grooves. I Tried to lube it with an anti seizing compound and that only helped for about a moto and the grabby feeling came back. I tried to file the area smooth and had the same results. I ended up getting a new master cylinder. I got a YZ master cylinder to get rid of the crappy KX brakes. Let me know if you find any thing that works, I still have my old master cylinder and my need it as a spare.

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Your problem sounds like my problem exactly. I even have some small lines on the master cylinder piston and lever. Oddly enough the bike is almost new (I'm guessing 20 or less hours). I'll try your idea for anti-seize and see if that helps. I'm thinking of hitting it with my air grinder with the finest stone that I can find to try to make it very smooth and see if that helps. I'm going to avoid the new master cylinder route if at all possible. :)

Thanks for the info!

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