Front braking issue

[xb12-2've-fun]

Hi All,

Recently i am experiencing an issue with my bike.
It doesn't appears when i am driving only but it does when i am using my front brake during braking activities.
My front fork is making a strange noice i think it is not making a strange vibration but i am not sure due to the general virbrations of my bike so if it does the vibrations is not severe.
Which made me rule out exessive wheel hub or bad tire. (Tire is only 1 year / 2000km's old)
At the beginning it was only by heavy braking at high Speeds e.g. +90km/h now i notice it also appears at +/-50km/h.

What i checked is
- wheel axle and brake cilinder isn't loose
- the sag of my front fork which is within the manual specifications.
- the rotation of my front wheel while liftend up, the rotor is sliding a Tiny Little bit against my Pads but not severe that it makes my wheel stop instantly. (It makes easily 3 turns).
- Braking pads have still enough body and are only 1 year (2000km's) old.

Can somybody give some input what i can check more or have any idea what can create this issue?
Thanks for your time and help guys!

Greetings

 

[user_deleted]

you either have a glazed rotor....faulty brake pads....a warped rotor....worn rotor-to-wheel attachment hardware....faulty front steering head bearings.....or a combination of all of the above. most likely it is in the rotor. perform the following checks:
1-with engine off and on flat smooth surface gently paddle forward and lock the front brake. if you here a clunk it is typically faulty steering head bearings. if you hear and feel this identical clunk at low braking speeds again it is the bearings.
2-if you are experiencing a pulsing type shake and can feel it in both the front brake lever and front of bike during light to moderate braking then you need to address both the pads and the rotor. i can provide the steps to do same once you determine from the above where the fault lies.

 

[xb12-2've-fun]

I assume it Will be my rotor and i should be a little surprised if they problem is lying at my pads as they are not that old.
I Will do the test today, thanks for your assistance.

So if i understand correctly i have to do all test with engine off.
Perform heavy braking, moderate braking and slow braking and determining while doing that if i hear a clunk or feel shaking than i know it is our my bearing protection my braking?

 

[xb12-2've-fun]

I don't feel a thing while braking no shivering on my steer nor on my brake lever. When i paddling with my bike it is difficult to create the issue what i am experiencing. But i drove my bike and i didn't feel a pulsing thing. What i do notice is a pulsing clunk while braking highly and intermediatly. So it is not a single clunk it happens intermittently and while my speed lowering down alse the frequency of the noise lowers.

Does that fits the causes for a faulty head bearing?

 

[Chicknstripn]

like Lunatic stated; if you can hear a clunk, while standing still with brakes fully depressed and rock the bike back and forth, you have a head bearing issue.
The description you've given of your brake performance leads me to believe your problem is in your front brake system. Clean the system thoroughly to rule out that your rotor is warped. Do the following:!Flush the brake fluid, remove caliper and pads, thoroughly clean piston area, while caliper is removed clean rotor surface with scotch bright pad. Also check rotor hardware to insure nothing has come loose, re-torque loose hardware. Try to clean the rotor hardware spring area as much as possible.
If none of the above helps then I would replace the rotor, hardware and brake pads.
Go to www.buellmods.com and download a service manual for a better understanding of brake system.
BTW What year is your bike and how many miles are on it? Is the brake system in question the original?

 

[user_deleted]

I don't feel a thing while braking no shivering on my steer nor on my brake lever. When i paddling with my bike it is difficult to create the issue what i am experiencing. But i drove my bike and i didn't feel a pulsing thing. What i do notice is a pulsing clunk while braking highly and intermediatly. So it is not a single clunk it happens intermittently and while my speed lowering down alse the frequency of the noise lowers.

Does that fits the causes for a faulty head bearing?

yes. you either have crap chinese brake pads that don't fit properly onto the locator pins...or the pad pins are grooved/worn and need replaced...or faulty steering head bearings. THE tell-tale sign is a pronounced "clunk". it's simple and it goes like this: if you can't paddle then just accelerate in 1st to approx. 10mph....shift into neutral...roll out a few feet...and lightly to moderately apply front brake and front brake ONLY. a clunk is the above.

 

[xb12-2've-fun]

Ok i will do the cleaning of the front brake as it is something i can do myself. Changing steer bearing requires tools which i don't have.

It is the original brake system. On the caliber there is written Buell but if it is the still the caliber from 2005 (year of fabrication) i can not tell as i am the third owner of the bike. The bike is in my position for 1y and 8m , it has 27700km = 17500 miles and i drove with it for almost 3000 miles not having changed the brake fluid once.

 

[njloco]

I really hope that he's not from the USA or, any other English speaking country.

 

[xb12-2've-fun]

Hi all,
An update on this topic. After disassembly my front brake calliper completly, cleaning it and bleeding my brake lines the issue was still there.

So i removed my front wheel and figured out that the bushings were worn. I changed the complete rotor set what i accomplished so far. Followed the manual how to do it but after reassembled everything i noticed something which is strange.

The front rotor i bought as a set. The springs are pusshing the rotor away from the wheel and the bushings are fitting together with the washers behind the bolts into the spaces foreseen in the rotor. So far so good.
Now after torqueing everything i noticed that my rotor is not in contact with my front wheel. The rotor is pushed away from the wheel caused by the springs behind the rotor also after the bolts are torqued at value and making contact with the bushings behind it.

I can play with my rotor in the direction of my front axle by pusshing it. Radial or tangential play i do not have which is good. But axial play i experiencing makes my unsure a little.

--> is this ok?

 

[xb12-2've-fun]

Made a small video to clarify what i just said in me previous reply.
https://youtu.be/ZH1jHSmno6Y

 

[Chicknstripn]

That is perfectly normal. That is what the springs are designed to do. I believe this give the rotor a "free floating" type characteristic and is suppose to assist with the heat dissipation/cooling of the rotor. It's also suppose to insure the pads contact the rotor evenly.
I'm not an EBR engineer so I may be a little off on my analysis of the spring function. Don't crucify me.
I will say that's exactly how my spring hardware functioned.

I haven't reread the entire thread but did you clean the rotor while you had everything apart?

 

[Silverrider]

What you have done is correct, with the EBR rotor mounts is a little different.

This kit replaces the stock front brake rotor mounting hardware. This mounting system increases the rotor to wheel contact, which improves the heat dissipating characteristics of the front brake system. It also reduces the brake drag of the system by keeping the rotor in better alignment in extended high temperature situations. These improvements provide more consistent lever feel for the racer. Recommended for use with: H0201C.08AZA 5MM FINNED FRONT BRAKE ROTOR H0201D.08AZ 6MM FRONT BRAKE ROTOR H0201.1B6 5MM FINNED FRONT BRAKE ROTOR. Also works with OE front brake rotor and offers improved heat dissipation over original hardware. Fits all XB and 1125 models.

http://www.erikbuellracing.net/store/models/xb12/front-brake-rotor-mounting-kit.html

 

[user_deleted]

item #74 in the schematic which is the factory rotor spring.....which installs into the rim hole at mounting point....is NOT used with the EBR hardware mounting kit. it is ONLY used with the OEM rotor mounting kit.

 

[xb12-2've-fun]

@Chicknstripn and @lunaticfringe. I have the OEM mounting kit not the EBR kit. Is this than still good?

To be honest of i think logically the bushing are fabricated together with the rotor as a set. The bushing thickeness is the only item that makes my rotor floats from the front wheel so my guess is that this is perfectly fine.

@Chicknstripn i cleaned my rotor system but i noticed Very quickly that the rotor was dammaged and the shape in the rotor was not alligned with the shape of the bushings anymore. This created free play of the rotor in the radial direction of the wheel

 

[Chicknstripn]

I was assuming you had replaced OEM hardware. My response was based on that.

I'd also assume that if the bushing receptacle(if you will) area of the rotor is worn so much that it doesn't properly hold the bushings, its time to replace the rotor. I do believe there is suppose to be some degree of movement between the bushing and the rotor. As you stated its part of the free floating design. Also, I believe the bushing are suppose to be installed in the rotor only one way. You might want to double check this. It's been a while since installed or messed with OEM hardware.

If you don't have a service manual go to www.buellmods.com and download one. That way you can get the correct info straight from the book.

Good luck

 

[Cooter]

Chicken is right and describing stock hardware clearly.:up:

There is good info here:
http://www.buellxb.com/forum/showthread.php?48151-EBR-Racing-front-rotor-install-instructions

It covers bedding the pads properly after replacing or cleaning the rotor.
I would also recommend only good pads such as EBC HH pads. Cheap ones will pulse if thats your issue. It's hard for me to decipher what your describing.