Hard braking shudder

[n3cr0]

Greetings all,

I have stiffened up suspension a bit for the track, but now under hard braking the front end shudders a lot.
I returned the settings to standard and increased the preload, the shudder is much less now but still there.

How do I get rid of this ?


Please correct me if I'm wrong. On the front shocks , compression settings are at the bottom and on the rear shock compression setting is at the top.

[gothy]

The shudder sounds like a warped disc. (but im not 100%)

Compression on the front is at the bottom of the forks yes.
Compression on the rear is on the reservoir

:D

[a_morti]

If you are high-speed feeling vibration through the front end and a pulsing through the lever (which would be worse/ more pronounced at low speed) then gothy is probably right.

Otherwise you might be describing the symptoms of using too much back brake, which means when you are breaking really hard, the back wheel "skips" locking briefly each time it leaves the deck, and giving what you describe. Similar feeling comes if you are changing down gear too aggressively or early, the back end will "shudder", but you will probably feel it through the front end.

I would iron it out by adjusting your riding style if it's my guess is right, softening the front might also help. If it's gothy's diagnosis then by replacing whichever disc is no good and giving the calipers a tidy up while you are about it. If you have cash and it's option number three, you could get a slipper clutch (else you could adjust your riding style)

Give us a more detailed description please?

[n3cr0]

It is not the back wheel skipping, I know that feeling :)

I did some tests, I got up to speed and pulled the clutch in and applied only the front brake, it still shudders.

The shudder happens when applying the front break at high speed, the shudder goes away when the bike has slowed down to about 90Km/h.
When applying the brakes at low speed it is smooth.

I have changed my suspension settings now to the settings in the suspension thread, this has improved it a bit.

But when slowing down from 180 Km/h it almost feels as if the handlebars are gonna get ripped out of my hands.

[a_morti]

Sounds like your brakes are at fault then.

[n3cr0]

:mad:

I really hoped it was something that I could fix without spending more money this month.

[gothy]

stupid question, your tyre pressure's are correct right?
Because that will cause that kind of feedback through the bars

[n3cr0]

It happens at track and road tire pressures

[jawhn]

Any chance of a slight dink on your rim / wheel out of balance? :CONF

[a_morti]

Any chance of a slight dink on your rim / wheel out of balance? :CONF

wouldn't have thought so if it only shows up on braking.

[houdini]

check your headstock bearings same thing happened me after a week off what the fu*k is wrong with my brakes i checked the headstocks and the were loose
hope it helps

[07BladeRider]

I definitely agree to check the rotors for warping. I (well, my wife now) have a set of Galfers on the front of the 900RR and there's an extremely small pulse when under hard braking.

I would say to check them out.

[Justin989RR]

Check your yoke bearing, and wheel bearings. Then I would check rotors for warp. Maybe have your tire rebalanced even?

[Big Kahuna]

The same thing happened on my '98 RR so I sent them to Mike at CTSmoto to check them out. He said they weren't warped so I had him resurface and full float the rotors for me. The problem went away and the bike brakes harder than ever now. :)

I think Mike charges $150 to float the rotors with your choice of rivet color, and an additional $50 to resurface and another $50 if you want to have the carriers re-anodized. :)

[n3cr0]

The same thing happened on my '98 RR so I sent them to Mike at CTSmoto to check them out. He said they weren't warped so I had him resurface and full float the rotors for me. The problem went away and the bike brakes harder than ever now. :)

I think Mike charges $150 to float the rotors with your choice of rivet color, and an additional $50 to resurface and another $50 if you want to have the carriers re-anodized. :)


That sounds like a plan, I'm also glad to hear that they have finished the highway between South Africa and America :D:D:D:D

[gixerkiller]

Greetings all,

I have stiffened up suspension a bit for the track, but now under hard braking the front end shudders a lot.
I returned the settings to standard and increased the preload, the shudder is much less now but still there.

How do I get rid of this ?


Please correct me if I'm wrong. On the front shocks , compression settings are at the bottom and on the rear shock compression setting is at the top.


before you start getting all crabby and listening to everyone try the basics first

tyre pressure
suspension settings
fork oil condition
steering bearing condition
wheel bearing condition
caliper condition

and the biggest one of them all, your brake lever pivot lubrication.

if all of these are perfect then you will need new rotors.

floating this and sanding that and modding this will not help if you can't diagnose the issue at hand.
it is like a steering dampner, it is a band-aid on ill prepared suspension

my years doing this are telling me that you have old fork oil,bad bushings in the forks, and a steering or wheel bearing issue.

believe it or not, i'm right more than 60% of the time on my diagnostics.

[a_morti]

60% is good odds on internet diagnosis with what is basically a fundamentally very vague list of symptoms...

Not that I doubt you (as you seem to be covering all bases anyway ;) ), but I would still go with a lightly warped disc.

[n3cr0]

60% is good odds on internet diagnosis with what is basically a fundamentally very vague list of symptoms...

Not that I doubt you (as you seem to be covering all bases anyway ;) ), but I would still go with a lightly warped disc.

The warped disk theory might just be spot on.

Yesterday I checked and serviced the steering head bearings and wheel bearings with no improvement in the shudder.
The brake calipers where serviced about a month ago , so i doubt that they are the culprits.
The brake rotors and shock oil will have to wait till payday, damn dentist has almost bankrupted me this month :)


I love internet diagnosis threads :V
As long as I don't end up being like the NOS guy :Laughs

[gothy]

I love internet diagnosis threads :V
As long as I don't end up being like the NOS guy :Laughs

hahaha yep lol :Laughs

[Big Kahuna]

For the record, I had changed the fork oil, checked the brake system and swapped out the fluids. Cleaned and checked the calipers, wheel bearings and even head bearings before sending the rotors to mike to have him check them out.

For me, resurfacing the rotors fixed my problem, but not everyone can or will do it. You can always send you rotors to Mike, I ship things all over the world with little problems. Turn around time would be a bitch, but you can wait until you riding season is over. :)

[n3cr0]

For the record, I had changed the fork oil, checked the brake system and swapped out the fluids. Cleaned and checked the calipers, wheel bearings and even head bearings before sending the rotors to mike to have him check them out.

For me, resurfacing the rotors fixed my problem, but not everyone can or will do it. You can always send you rotors to Mike, I ship things all over the world with little problems. Turn around time would be a bitch, but you can wait until you riding season is over. :)

Funny story about that "riding season" , in SA it is riding season 365 days of the year :V

[Big Kahuna]

Funny story about that "riding season" , in SA it is riding season 365 days of the year :VYeah, that's the way it is here, I ride year round which makes it hard to give up the time to make big changes to the bike. Now that I have a few more bikes in the garage, it's easier to make such changes since there is always something else to ride. :)

[n3cr0]

I have noticed that my brake disks do not move from side to side. But they do move forwards and backwards. How bad is this ?
From what I understand, front brake disks should move a bit from side to side (floating) , is this correct?

I tried cleaning the rivets on the front brake disks, the shudder now seems a bit less. Or it could be that I'm currently reading Keith Code's Twist Of the Wrist V2 and that my riding has improved a bit :)

When moving the outer ring of the front brake disk I can hear a grinding noise, what would be the best way to try and clean out these rivets without replacing them. I'm considering buying a high pressure washer to blow the crap out of the disks, cos around here they are cheaper than replacement disks.

Opinions please.

[gixerkiller]

I have noticed that my brake disks do not move from side to side. But they do move forwards and backwards. How bad is this ?
From what I understand, front brake disks should move a bit from side to side (floating) , is this correct?

I tried cleaning the rivets on the front brake disks, the shudder now seems a bit less. Or it could be that I'm currently reading Keith Code's Twist Of the Wrist V2 and that my riding has improved a bit :)

When moving the outer ring of the front brake disk I can hear a grinding noise, what would be the best way to try and clean out these rivets without replacing them. I'm considering buying a high pressure washer to blow the crap out of the disks, cos around here they are cheaper than replacement disks.

Opinions please.


floaters should not move much, they move but they should not rattle or grind.

check the aluminum hub for grooves worn by the buttons, if you have these you will need to replace the rotors.

my yzf 750 had full floaters and they did the same thing- ate the hub at the pins, had to replace the rotors twice before i uncovered the truth, the 6 piston calipers were to blame, constant cleaning and rebuilding was the only fix.

[Grebo]

If you're braking really hard on tracks then it's probably the bump stops in your forks. The only way around it is to see a suspension specialist and get them upgraded.

[n3cr0]

Guess what has just arrived :V

[Big Kahuna]

Guess what has just arrived :VNew?

[jawhn]

Wow. Nice. What'd that set you back? :CONF

[n3cr0]

Brand new, still in the plastic wrapper :)

Cost me R6200 for both, OEM from Japan.

[jawhn]

Holy mother of god... :eek:

If you're talking Rands, that's $845.167 USD as of today. Lordy.

You can almost buy a used, beat-up 900RR for that, nowadays. Yikes. But cool that you got them.

[n3cr0]

Holy mother of god... :eek:

If you're talking Rands, that's $845.167 USD as of today. Lordy.

You can almost buy a used, beat-up 900RR for that, nowadays. Yikes. But cool that you got them.

Yip, I also shat myself when I heard the price. But trying to find second hand ones or having mine rebuilt took too long.

I should be getting my paddock stand tomorrow. I ordered one of those that fit onto the triple clamps and lifts the whole front off the ground. I will be doing a suspension fluid replacement as well.
So by Monday I should have a stable front end :V
Then is't trackdays till wallet can't take it anymore :EG

[n3cr0]

OMFG, I have just fitted the new brake disks and gone for a ride.
You would not believe the difference, no shuddering or shaking and she stops really fast :V

[jawhn]

OMFG, I have just fitted the new brake disks and gone for a ride.
You would not believe the difference, no shuddering or shaking and she stops really fast :V

Yeah, I can only imagine what a difference that would make, if you had gotten "used to" them being all wack-ass! :EG Cool!