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Front end shake when braking
- Thread starter Tazman2
- Start date
An update for the update. Drag is gone not sure why I didn't post that as a separate post but whatever. Shake still remains when I took the bike out a week or so ago when it hit 50 degrees for once and the roads weren't too bad! Today I checked the rotors with whatever I could find flat and held it there. Nothing obvious. But how much run out needs to be there to give you violent front end shake at high speeds like I have? Bearings seem fine no noise when I rotate the tire except for the brakes slightly dragging for a moment as it rotates. Warped rotor just a smidgen!? Head bearing seems fine too except for some very tiny play that almost feels like normal fork play if there is such a thing. Last time I tried to get rid of that it made the bike not want to go straight...
Bought a dial indicator today and mount for under $30 at Harbor freight. One side is .003/4 ish run out and other side is .008/9 ish run out. From some google searchs the GSXR guys say the manual shows .012 as being "acceptable". I assume ours is roughly the same? Is it possible because one side is soo much more its creating this odd situation?
Just found some random info on "floating" discs with a good easy solution to warped disc symptoms.
The non floating issue is a common one with the Brembo design. Here's a way to get them to float without taking the whole thing apart: Use a 6mm allen head cap screw that is about 1/2" longer than the width of the bobbin. Run the screw through the bobbin and lock it in place with a lock nut. Chuck the appropriate allen socket in an electric drill and use the drill to spin the bobbin. You might need to tap the bobbin with a small hammer to break it free but when you get it to spin you will dislodge the crud that is holding everything in place and keeping from floating. I could do the fronts on my Ducati in about 30 minutes, good for a year or so.
The non floating issue is a common one with the Brembo design. Here's a way to get them to float without taking the whole thing apart: Use a 6mm allen head cap screw that is about 1/2" longer than the width of the bobbin. Run the screw through the bobbin and lock it in place with a lock nut. Chuck the appropriate allen socket in an electric drill and use the drill to spin the bobbin. You might need to tap the bobbin with a small hammer to break it free but when you get it to spin you will dislodge the crud that is holding everything in place and keeping from floating. I could do the fronts on my Ducati in about 30 minutes, good for a year or so.
^^^This. I'll bet good money and a beer that you have a cupped front tire. Same thing happened with a Bandit I had. Couldn't see the cupping easily, but as soon as I put a new shoe on the front, the problem went away. Happened with both Michelin Macadams and Bridgestone BT020s about 3/4 of the way to the wear bars.
Switched to Pilot Powers and never had the issue again.
Taz,
Also take some 600 grit sand paper and with the calipers off the disc
lightly sand in a circular motion inside and outside the discs. Much easier when dismounted.
Clean and wipe thoroughly with brake cleaner and rags.
You may just have some pad material build up on a disc. It doesn't take much to cause a pulse and you will remove little if any actual metal from the discs.
Just be sure to do it by hand.
Also take some 600 grit sand paper and with the calipers off the disc
lightly sand in a circular motion inside and outside the discs. Much easier when dismounted.
Clean and wipe thoroughly with brake cleaner and rags.
You may just have some pad material build up on a disc. It doesn't take much to cause a pulse and you will remove little if any actual metal from the discs.
Just be sure to do it by hand.
tomc
0
That would be my guess, also. I'm thinking is that warped disks would cause the forks to piston up and down, not side to side.
Taz,
How many miles do you have on the front tire and how does the tread look?
Usually I've seen (severely) cupped tires cause head shake while riding and (or not) braking.
How many miles do you have on the front tire and how does the tread look?
Usually I've seen (severely) cupped tires cause head shake while riding and (or not) braking.
I'd normally consider it but I have ZERO shake during decel with and without hands on the bars. When hitting the brakes is when it goes to heck. And I don't recall ever saying side to side it may very well be a up and down vibration. Its pretty brutal at higher speeds! I will try the button cleaning and bought some 80 and 100 grit sand paper from suggestions during my googling to clean the rotors. Supposed to be 50s this weekend so gotta get on this one of these days when the snow and freeze calms down! :p
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When measuring runout are you checking thickness, or actual true of the rotor in relation to the caliper?
I bent a rotor on my CBR 1000 just by putting it in a wheel chock while towing. Rotor got bent, I had no idea. Front would heat up and drag on the racetrack. Braking was offonoffonoffonoffon at speed and caused concern under hard braking. Replaced rotor, issue gone.
I bent a rotor on my CBR 1000 just by putting it in a wheel chock while towing. Rotor got bent, I had no idea. Front would heat up and drag on the racetrack. Braking was offonoffonoffonoffon at speed and caused concern under hard braking. Replaced rotor, issue gone.
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I'm no pro[Bill??}, but tire looks like it was severely UNDERINFLATED and worn UNEVENLY[maybe cupped?] I suggest a new tire for starters[at proper inflation] Good luck.Just took a pic of the tire. Doesn't seem that bad versus other ones I've had!
achesley
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Once., in 2002, I had changed out the front tire on my '02 R1150 GS. From new., it had a little wobble at a certain speed with hands off the bars, and, later developed into a hard braking slight wobble also. Changed the front tire and all of that went away and never came back though the next 5 or so fronts that were installed. It was just that one tire and I replaced it with the same brand and type tire. Heck back then, on BMW GS's you didn't have a big choice till later years and it was even worst on tire choice in '95 on my first R11GS.
I'd change that front tire 1st.
I'd change that front tire 1st.