F800GS Fork Clack Noise/Feel

Discussion in 'Parallel Universe' started by The Griz, Dec 17, 2010.

  1. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    I have recently seen a lot of random mentions within other threads regarding the fork clacking noise/feel on the front end of the F800GS. Most of the mentions unfortunately have shown misinformation on the subject and/or shown someone altering components on their bike that have nothing to do with the actual instigator.

    The fork clack noise/feel is absolutely without a shadow of a doubt not from the plastic x shaped spring guides that ride on the damping rods inside the forks! Those black plastic x shaped spring guides do not move on the damping rod, and do not make contact with anything other than the inside of the springs. I've been inside my forks 4 times. The black plastic x shaped spring guides "snap" into position on the damping rods as to not move. They don't move therefore do not hit the fork tube cap therefore do not make a clacking noise. I've marked up a parts schematic to point out the facts:



    [​IMG]

    #3 is what certain people claim is the clack-making culprit. It is the back plastic x shaped spring guide. It has a small steel ring that sits inside it in a groove (#4). #3 with #4 inside it slides onto the damping rod. The damping rod, as you can see, has a groove where the spring guide "clicks" or "snaps" into position, FIRMLY. I suspect that there MIGHT be some forks that are coming from Marzocchi without one or both of the spring guides snapped into place. If you open up your forks and the back x shaped plastic spring guides move up and down on the damping rod, this means simply that they are not snapped into place on the groove on the damping rod. Snap them into place and you're done (it requires some elbow grease to snap them into place, but this is a good thing and how it was designed. Once they're snapped into place you will not ever have to remove them again. They should have been snapped into place at the factory). No little rubber pieces or other voodoo needed.

    All of that said and demistified, I'd like to point out that I have gone for rides with both of the black plastic x shaped spring guides both unsnapped and loose on the damping rod and snapped into position. No difference. No change. Sounds and feels the same either way.

    Why?

    This is because the clack sound and feel does not originate from these spring guides! Or anything inside the forks for that matter!

    It originates from the Brembo floating front brake rotors. Nothing else. The rotors float a bit more than others designs. So when you go over bumps you hear and feel "clack clack".

    This is absolutely fact here folks. I've been experimenting with it for two years. I've opened up and altered fork components many times, tightened steering head bearings many times, etc, etc... The only thing that has ever cured it is removing or hindering the "float" in the stock Brembo front brake rotors. If you don't believe me, test for yourself. CAREFULLY go for a slow ride away from traffic with both of the front brake rotors removed.

    Or, as a safer option, use some zip-ties to inhibit the excessive floating motion within the rotors:

    [​IMG]

    [​IMG]

    What's that? Silence? Exactly.

    If you want to permanently fix it, buy and install some aftermarket rotors of a different design (non-floating), or with less "float". Two companies I have found that make them: Braking and Lucas.

    http://www.wunderlichamerica.com/motorcycle/F800GS/8130021.html

    http://f800depot.com/twalcom-wave-front-disc-p-467.html

    This is not "The Griz's theory" on the subject, or my "opinion". What I've stated above are the facts. Heed them and welcome to a clack-free world. Cheers.
    #1
  2. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    Oops, sorry. Corrected in OP.
    #2
  3. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    That's what I've chosen to do as well! Didn't bother me anymore once I knew what it was!:D
    #3
  4. toowheels

    toowheels on a mission...

    Joined:
    Mar 5, 2006
    Oddometer:
    969
    Location:
    Vancouver, BC
    Hey Griz,

    Thanks for going through the effort and posting your results! :thumb

    Less clacking or at least knowing exactly what it is will hopefully lead to less :becca

    I wonder if the disc mounting "pins" (rivets or whatever) could be compressed tighter to eliminate some of the slop?

    Hmmm...

    Dave
    #4
  5. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    No prob! I love to help the forum out, especially with correct information!:clap

    That's a good question about compressing the pins or rivets or whatever they are. Let me know if you figure something out.
    #5
  6. bodhizafa

    bodhizafa How hard can it be?

    Joined:
    Jan 6, 2010
    Oddometer:
    653
    Location:
    Louisville, Co.
    I noticed a lot of play with the rotors the other day putting my front wheel on. I was getting worried. Is all that play normal?
    #6
  7. blender

    blender Just another rider

    Joined:
    Jul 27, 2004
    Oddometer:
    727
    Location:
    The Middle Coast
    Uhmmmm, Griz? You're forgetting this is an Interwebs forum. You're not supposed to supply correct info, only vague answers gleaned off some other forum, or obtained while talking to a mechanic's brother's friend. :)
    #7
  8. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    The play is normal. I have not seen or heard of a stock front rotor on an F800GS that doesn't have excessive play. It falls under the "they all do it" category.

    Before keyboard jockeying it and claiming otherwise, go out to your F8, grab the rotors, and push/pull. Lots 'o play right?:nod

    Brembo, for some odd reason IMHO, puts an excessive amount of play in the front rotors for this bike. Far too much. So much so that they make a clunk/clack noise/feel when going over any bump. A certain amount play in the friction plate of a floating brake rotor is good. This minimal play allows the outer ring (friction plate) that makes contact with the brake pads to expand and contract independently from the hub, reducing warping under intense heat. There are other reasons as well, but this is the main and most important reason floating is better. But again, it's obvious that Brembo is putting far too much play in these rotors.
    #8
  9. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    :lol3:clap
    #9
  10. Xskydiver

    Xskydiver Been here awhile

    Joined:
    Aug 6, 2006
    Oddometer:
    266
    Location:
    Willcox, AZ
    That all sounds very convincing. I went out to the garage and gave my brake rotors a good shaking and didn't get much movement or any noise. I'm wondering now...If the klacking is definitely NOT from the forks, then why does everyone who installs the klack stoppers report the klacking to have stopped? I haven't tried either method yet. I pretty much don't think about it until I'm on the wash board.
    #10
  11. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    If you have the clack, the movement (play) in your rotors is there just enough, trust me. I've spent two years researching this.:deal

    I've not read or seen these results you speak of. :hmmmmm

    The black plastic x-shaped spring guides that ride on the damping rod ABSOLUTELY snap into place FIRMLY on the damping rod. Therefore, these black plastic x-shaped spring guides do not move on the damping rod. If they cannot move, then they cannot "clack" up against the fork tube cap, making the use of a rubber bushing between said black plastic x-shaped spring guide and the fork tube cap useless. If your black plastic x-shaped spring guides are snapped into place properly, they are ABSOLUTELY NOT the culprit.

    If you're so bent on proving me wrong, check for yourself. Go out and zip-tie your rotors like in the picture above. Ride over "washboard". No clack.
    #11
  12. tmex

    tmex Long timer

    Joined:
    Apr 20, 2006
    Oddometer:
    2,039
    Location:
    NorCal
    Yes, it is the rotors. A safe and simple way to prove this is to find a section of cobby pavement that produces the clack. Then ride over it with the front brakes lightly applied to keep the rotors from moving freely, and the clack will not occur. I posted this early on when Griz was "actively" pursuing the clack, but it apparently got lost.
    #12
  13. ebrabaek

    ebrabaek Long timer

    Joined:
    Jan 12, 2010
    Oddometer:
    4,912
    Location:
    Grand Valley, Colorado
    I`m with Griz on this one as well...... Before I joined this forum.... I bought the $10 "clackstopper"........Made no difference.......Investigating further.......Sure enough.....the rotors were it...... Does`nt have to be fancy...... Just go out and grap the rotor.... You can yank it up and down about 1-2mm.....:thumb:thumb

    Erling
    #13
  14. Xskydiver

    Xskydiver Been here awhile

    Joined:
    Aug 6, 2006
    Oddometer:
    266
    Location:
    Willcox, AZ
    Lighten up Francis :D

    I'm not interested in proving anyone right or wrong. I don't care enough either way. I'll try it out. It's easier than the klack stopper and free. I'll try safety wire probably though. It might look better. A more permanent solution might be a little JB weld in the joints.
    #14
  15. TBickell

    TBickell Been here awhile

    Joined:
    Nov 14, 2010
    Oddometer:
    231
    Location:
    Somers,MT......Anthem, AZ
    so then we should go and kill the "klackstopper guy" ..:1drink
    #15
  16. transalp russ

    transalp russ Gadget Addict

    Joined:
    Nov 14, 2006
    Oddometer:
    25
    Location:
    Oxford UK
    Great write up Griz, I went through a similar procedure and came to the same conclusion, it was the brake rotors.

    On comparing brakes on my brother-in-laws Aprilia Dorsoduro, exactly the same, so I just presumed the play was to cope with expansion due to heat?? maybe.

    Anyway best cure I've found is get on with enjoying the ride and not worry, earplugs also help :rofl
    #16
  17. yzfcathy

    yzfcathy Weeble

    Joined:
    May 9, 2007
    Oddometer:
    1,222
    Location:
    TUS LAS
    So, before y'all go out to your garage and stop the mean old clack monster...you may want to do a little research and see just what floating rotors do for you.

    They can be at least, a performance enhancement for removing excess friction caused between the brake pads and the rotors.

    Most importatnly though they (floating rotors) will save your ares if you ever get enough head shake to spread those brake pads apart enough to cause you to have to frantically pump on the brake lever to build up pressure again.

    The day it happens to you will be the day you run to get floating rotors installed on every bike you have.
    #17
  18. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    Um, yeah, no one's saying that permanently restricting the floating movement of the rotors is the way to go. Rather, the goal was to diagnose the problem. We've done so.

    I posted the benefit of the floating rotor design in post #9 of this thread. We're well aware of the benefits of such a design.

    I've also stated prior in this thread that the clack of the floating rotors does not bother me now that I know that it's normal. I'd advise others also that permanently hindering the rotor's float is a bad idea. The zip-tie/safety wire trick is only for a temporary diagnosis as proof.
    #18
  19. yzfcathy

    yzfcathy Weeble

    Joined:
    May 9, 2007
    Oddometer:
    1,222
    Location:
    TUS LAS
    Sorry if I offended you Griz, my intent was only to shed light on the good side of floaters. I also appreciate your diagnostic work here. I never saw anything about the plus side of the floaters, thus my post. No disrespect meant at all.
    #19
  20. The Griz

    The Griz North Forest Rider

    Joined:
    Nov 26, 2008
    Oddometer:
    3,787
    Location:
    Minnesota
    No worries mate!!:D

    I just wanted to make sure we're on the same page.
    #20