My front brake sucks! What could be the problem?

[nikki]

My front brake is pathetic. After riding some of the new thumpers, it made me realize even more how much my front brake sucks. I have to grab it as hard as possible just to slow me down some resulting in massive right hand cramps after a few hard laps.

So what could be the problem? Air in the line? Worn pads? Glazed pads? Low brake fluid? Problem with the line/caliper? How can I check/fix these types of things?

 

[bclapham]

Nikki: the yamaha brakes are rubbish- on my yz250, i ran the braided shorter line and also pads from the honda. and it was still crap, nowhere near as good as the brake on my rm with the stock routing and way old pads! i think its the master cylinder since the calipers are all the same on most models- i bought a complete front brake from a CRF450 from ebay cheap- if i were you, call service honda and get the master cylinder from a CRF/late CR and get the shorter braided line- its the same as the RM master.

 

[Rcannon]

I agree. I fought the front brake on my 97 YZ 250 for quite some time. I tried a shorter line, new pads and a new rotor. It helped some, but not much.

I bought a used mastercylinder from a CRF 450 and installed it. The brakes are at least twice as strong. I recommend this to anyone .

 

[marcusgunby]

But the strongest brake comes from using a 03/04 KX setup-you may find this hard to get for reasonable money.The cr brake system comes a close second.

 

[Rcannon]

Marcus, I will keep my eye peeled for a front KX m/c. Any idea why they are stronger?

 

[marcusgunby]

They(KXs) use a totally different caliper that luckily still mounts up on the same points as the CR/YZ type setup(at least on a RM it does)im thinking it has smaller pistons.

 

[marcusgunby]

forgot to say-the lever is rock solid once bleed properly(on the KX setup)

 

[ericlachance]

Rcannon, You really recommend using the crff mc? I have a 96 yz and I also think the front brakes are...well...CRAP. I put in new sintered metal brake pads wich cost me almost 80$ and that didn't do much, brakes were bled and there is no air in the lines...seems like the next logical stpe is the mc setup. Where did you find your master ccylinder and how much should I expect to pay?(don't want to sound cheap, but I just had to get myself a new pair of glasses, so here I am, 600$ later and a full time student...)

Thanks

Eric

 

[bclapham]

www.servicehonda.com

www.ebay.com

:thumb:

 

[Rcannon]

Eric, YES!!!! 

I misspoke earlier about it being from a CRF. I placed a bid on a crf, but ended up losing that one. Mine is from a 2000 CR 250.   I paid 30.00 off of ebay.  It would have been worth it paying full retail.  Here were my dollar totaly and (in my opinion)  how much it helped.

 

EBC brake pads......slim to none                  25.00

new rotor                                                     98.00 +10%power increase

Short brake line, mount, and new fluid.      125.00 +10%power improvement 

Rebuild kit for stock M/c                                25.00    same as before 

CR master cylinder (used)                             30.00 +30% power improvement

 

It was the best mod I did to the brake system. It is also much cheaper than my other thought of an oversize rotor at 199.00. Find a used one and go for it. My brakes feel as good as anything else I have rode (including an 04 YZ 250). I never say things like this, but I can almost promise you will be happy with the improvement. I would have loved to try this with the stock line. I think the "CR routed" stuff is a bunch of bs.

 

 

[Studboy]

Rcannon, how did my brakes compare to yours when you rode my bike?

I don't think that the stock 02 YZ250 front brake is that bad. Miles ahead of my 94 KX250. It is still not quite as powerful as the CR's that I have ridden, but it is enough.

 

[Rcannon]

Stud, I thought they felt very similar. Yours was decent.

The master cylinder change brought mine up to that level. Mine was awful before making the switch. I would have been very happy to have the brake power your bike came stock with. I had to spend 300.00 to get into the neighborhood!

 

[n8MX]

I have the same problem (weak front brake) with my 98 KX250. It appears that master cylinder replacement would be an easy way to go, a new CRF450 m/c is $85 from Service Honda. Could this be used with the stock caliper? Just screw the banjo bolt into the new master cylinder and bleed the system? Seems pretty simple... I'll have to think about doing it if it is really this easy. The CRF brakes are much, much better than my KX brakes, it would be great to improve mine.

Andy

 

[bclapham]

it will probably work but the cr banjo has a slight bend so it will clear the bars properly (the cr master bolts from the back)

your best bet is get the cr master cylinder and a cr style braided line from galfer or someone similar- they arent that expensive and i will be well worth it when you want to brake nice and late and take that inside line!;)

 

[Rcannon]

I followed the advise of Mr. bclapham when I did my conversion. My used m/c included the banjo bolt, so I never noticed the bend. I THINK it might have worked with the stock line.

No matter . It is worth it even if you have to buy a new line. The ride engineering line is the way to go. It lets you move the fittings for the perfect allignment.

 

[marcusgunby]

Sorry to spoil everyones fun here but the KX(old and new) master isnt the problem-the 03KX still has the same and its super powerful,on the YZ i think the Akabono one isnt as good as a CR/KX type. So the advice would be if you have a YZ get a KX/CR master cylinder, if you have a older KX you really need a 03 KX caliper-the disk is even still the same on the 03 kx and i always thought that was a problem-live and learn i guess.

 

[Rcannon]

Marcus, do you think the soft feeling comes from caliper flex? I believe the Akabono master cylinder was sub-standard as well. The adjustment was a pain in the rump. Do you remember the article from MXA (year 2000???) that had some sort of article on improving the brakes on the YZ? Some company named Dog Town racing had mods for the m/c and caliper. I wonder if they are still around and what the did?

If I remember correctly, most of the good brakes (new and old) have the Nissan master cylinder. Usually they have "11" stamped on them somewhere. I dont see how much could change if a person was substuting a "11" from an identical one.

Bleeding is very important. I never did get a good bleed until I used the mity-vac. That and leaving the lever pulled in all night (thanks duct tape) did the trick for me.

 

[marcusgunby]

I think its a bit of a mystery, as the pre 03 KX front brake uses a CR type caliper and the CR had firm brakes.Maybe its more the mounts on the fork legs??Maybe the pre 03 KX and YZ are just badly bleed from new? i know KTMs seem to suffer from this problem, some have massive stopping power and others have almost no brakes at all.

On the master cylinder sizing, dont forget its also important the leverage ratio placed by the lever-maybe the YZ setup doesnt have the leverage a CR or KX one has.The YZ i have rode had a reasonable brake(for power and firm feeling lever) but didnt have the progressive power i like, they work ok as you initially pull the lever, then you pull harder and you get a sudden lock up.

 

[Jaybird]

nikki,
You might want to completely change your fluid out. Brake fluid tends to draw in moisture real fast and it can make things spongy.

Also, I would also recommend one of theose vac type bleeders.

 

[bclapham]

LOL. the 2001 yz250 has a nissin MC but the 2001 yzf426 has the akebono- IMO they are both crap, and the nissin on the yz250 is different from the cr/rm nissin since the cr/rm MC bolts at the back. i think the 2001 kx250 has the same setup the yz250 and thats crap also.

i tried everything on my yz-line-- ppads, constant bleeding and flushing and it was never as good as the stock rm that had never been opened even after 1 season.

 

[fmfkx125372]

Nikki...Try this...I had similar complaints about my 03 125sx, but after doing this, they are rock solid! Got this off of the ECEA site, but you need to be a member to view...So I'll try post it here...

Go to pepboys or Home Depot and find yourself a syringe and tubing that will fit over your bleeder nipple. The fork bleeders will work too if you have one handy...

Take the master cylinder off and caliber....Try and purge as much of the old fluid out as possible. Dump the remaining out of the master cylinder. Fill the syringe up with your new fluid, and get the line as straight as possible. May need a helping hand or a clamp. Push the tubing onto the bleeder nipple, and force the new fluid through the system until you see zero bubbles and that's it...I'm sure you have some moisture/air in your line. The YZ brakes aren't the top, but they shouldn't been that soft...

Good Luck!

 

[mxer842]

"My front brake is pathetic. After riding some of the new thumpers, it made me realize even more how much my front brake sucks"

your front brake is prolly fine, the 4strokes just have more decompresion braking which makes it slow down quicker than 2strokes.

 

[bclapham]

Originally posted by mxer842
"your front brake is prolly fine, the 4strokes just have more decompresion braking which makes it slow down quicker than 2strokes.

none of the yamahas i have ridden of late have brakes anywhere near as good as the rm's, cr's and 03kx's wether they were 2 or 4 stroke.

 

[mxer842]

he said that he had noticed it on the new thumpers, and they do have some serious decompression braking compared to 2strokes. its a logical conclusion to come to.

 

[nikki]

Originally posted by mxer842
he said that he had noticed it on the new thumpers, and they do have some serious decompression braking compared to 2strokes. its a logical conclusion to come to.

Uhh... first of all, I am a she and second, my Yamaha is a new thumper as well. Please read before posting goofy stuff. :moon:


FMFKX - thanks for the bleeding advise. I put a new brake line on a YZ 80 of mine once and it was HELL getting the fluid all through and everything working good. I think that's why I fear trying to bleed the front again. But it sounds like it should help because I'm pretty sure the brakes have gotten progressively worse and the pads aren't that worn.