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Any stiff levers?

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Title sounds a little weird, but am I the only person who`s front brake is bad or do I just complain alot?haha Im pretty sure that all braking systems do the same thing? Push oil through a hose that pushes out two pistons that make two pads squeeze on a disc? So why is it that different systems have different lever feel and modulation? I can understand pads and disc making them perform better, but why is it people only like Yamaha brakes, when its a Honda set-up?? Basically im just trying to see if anyone has got there stock set-up to feel like a Honda set-up or better, if so, please tell, it would really help. I mean REALLY help. Every thing on the set-up is like new, and I have been using a MityVac to vacuum bleed.

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Size of the pistons in the caliper and master cylinder have a lot to do with feel. Still having problems with your brakes I take it? The lever comes back a lot or weak braking force? Have you tried SS brake lines? Do you have a problem or you just want something that you don't have? It might be the brakes are working just fine but you felt brakes on a different bike and want those brakes. It's like somebody buying a 250 but rode a buddy's 450 and now trying to buy every single part they can trying to make their 250 feel like a 450. If you want Honda brakes then buy a Honda

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I understand what you mean and feel the same. My new 2012 yzf250 doesn't have the same stiff feel front brake that my old Honda 2010 did have. My yamaha brakes brake good but you have to pull it harder and longer to get it to brake.

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It is all based on leverage.....Haha! (pun intended)

The amount of force applied to the wheel during braking can be broken into two components;

The ratio of movemnet between the lever and the caliper piston, and the distance from the axis of rotation of the wheel to the location of the brake pads.

The ratio of movement between the lever and caliper piston defines how much pressure multiplication you have when you pull on the lever. To to get a fixed amount of caliper piston movement (or equal amount of aplied pressure) you can have a long travel of the lever but with a light feel or short travel of the lever with a heavy feel.

By reducing the diameter of the master cylinder piston (or increasing the length of the lever) you have the first setup. By increasing the diameter of the master cylinder piston (or decreasing the lenght of the lever) you get the second.

The placement of the caliper farther from the wheel will increase the effectiveness of force applied at the caliper. For a given equal amount of lever force, a brake caliper mounted farther from the axle will provide more stopping force.

All of this goes out the window if you have any air trapped in the hydraulic system. Since the air compresses (fluid will not) the ratio of lever movement will be way off.

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Your '09 250F has a great front brake when it's working good. I don't think you need to go the trouble of swapping master cylinders or anything like that. Front brakes are a HUGE p.o.t.a to bleed. I'll go through a half bottle of brake fluid before I'm happy. It just takes A LOT of patience.

Oh, cheap brake fluid will not help your problem either. I learned that lesson the hard way. I have a buddy that is brutal on rear brakes (goes through 2-3 sets of rear brake pads season). Put a new rear brake hose on his bike and the first time we went riding he almost blew through a barbed wire fence because the brake fluid boiled in the rear caliper.

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Stated by Swede it also is the ratio of the size of the Master cylinder piston to the caliper piston. KTM have great brakes but they feel spongee when the pad wears half way down the cure change the pads with new ones. The KTM probably has a smaller master cylinder piston than say a Yamaha. So yo don't move a lot of fluid but you do get a lot of force. The other issue is a bradided steel line stops any expansion of the line when the brakes are applied.

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Sure you don't have a bent rotor or something like that going on?

Rotor doesn't have to be tweaked much. All it takes is a warp of .020" to really mess brake-feel up.

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Try using a good quality fluid. I've had very good luck with the Motul DOT5.1 or the Motul RBF600 for riders who get their brakes *HOT*. The front brake lever adjustment (distance from the grip) can obviously make a difference but so can the master cylinder position (make sure the cap is close to level and it isn't too close to the throttle housing). Sliding it closer towards the center of the bars will give you a firmer feel since you'll have less leverage. If the lever is adjusted so tightly the master cylinder push rod doesn't return 100%, it can prevent the brake hydraulics from functioning correctly if the return port is restricted/blocked.

I've also seen brakes that feel a bit spongy but are very strong when being ridden. Cheesy quality brake pads can make the brakes feel weak- The EBC red pads are a prime example. Best thing to do with those is throw them at the neighbors cat when its in your garbage can.

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Well I was told that if it was rotor, it would grab then free up then grab again. I don`t think it does that. And I wish my brakes were soft with good power. And like David said about his 2012, is it maybe just how Yamaha`s are? Ive never seen a magazine complain about Yamaha brakes, in the MXA 450 shootout, the YZ got second, behind the KTM`s.

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Well I was told that if it was rotor, it would grab then free up then grab again.

No, not the case. The rotor is fairly flexible and when you grab the brake, you'll never really feel it. It will just feel like you have air in the system.

Disk brakes on cars and trucks are very rigid and you can really feel it when you apply the brakes, but your YZ wont exhibit this trait.

When you have a small amount of warp, the rotor pushes the caliper pistons back into the caliper when there is no force applied to the lever. When you do grab the lever you have to take up the extra gap before the brake grabs.

You are correct about he Yamaha brakes being good from the factory. My '06 YZ and my wifes '07 WR have great front brakes. But i had to bleed the crap out of them to get them that way.

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It doesn't take much of an impact to tweak a rotor. I've bent a few. The best way to check if a rotor is bent is with a Dial Indicator, but I doubt you have one.

Set the bike on a stand. Back out one of the axle pinch bolts (on the brake side) so you can stick a 6 inch long piece of coat-hanger wire with a small hook bent in it under the bolt. Tighten the bolt enough to hold the wire, and bend the wire so the tip is almost touching the rotor (the closest you gan get it, less than 1/16th inch, near edge of the rotor). Slowly rotate the wheel and and watch the space between the tip of the wire and the rotor. If the gap changes any amount at all, the rotor needs to be tossed.

When you bleed the brake, take the cap off the master cylinder and fill it to the top. Put your vac pump on the bleeder screw and open the scew 1/2 turn. Pull a vacuum on the bleeder and watch that the master cylinder doesn't go dry. Keep adding fluid untill you have a sleady flow of fluid into your vac pump. After you have a good flow of fluid, pull the hose off but leave the bleeder screw open (don't touch the brake lever). Gravity will pull fluid from the master cylinder and out the bleeder screw. If only fluid is leaking out of the bleed screw and no bubbles you should be done. Close the screw and check the brake.

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I gotta try that. And every time I use the MityVac, I always get little bubbles, some times big, in the line. I put teflon tape on the screw and I am sure there cant be that much air, I filled that catch can twice with fresh fluid. I was thinking put a nice seal of grease around the threads too? It cant suck in grease can it?

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Do what O_0?haha

you bassically do what you do when you're replacing brake pads on a car. you just loosen the bleeder on the caliper remove the pads and put a c clamp on the piston and back of the caliper squeeze it till it's back as far as it will go and tighten the bleeder. put the pads back in put on the bike and then bleed the brakes. did this to my truck last night and it basically fixed the dragging/waytoostiff brake feeling. it's just a thought. i'm probably wrong but if you're out of ideas...

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