12,000 service and chain recall - bike riding noticeably different

Discussion in 'Parallel Universe' started by TastyPants, Sep 14, 2010.

  1. TastyPants

    TastyPants Harasshole

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    So I took my bike in for the 12000 mile service this weekend. They also did the chain and sprocket replacement due to the recall. Valves were within spec so no adjustment. The tech also noted that the "Judder Damper" had cracked and needed to be replaced. He mentioned that usually this doesnt need to be checked until 18k but they looked and it was "broken" so they replaced it. Sounded fishy and would appreciate if someone knowledgeable would tell me how I might have broken it, and any other damage I should watch out for as a result. Although thats not really what this post is about...

    I first noticed on the way home from the dealer but today was my first regular commute on it. The bike is riding a lot differently than it was before. There is definitely no snatchy throttle anymore at all. IN fact it feels a tad bit more sluggish, but this might just be because it isn't as snappy and is psychosomatic... It feels a bit like a different bike so I am little worried, but if its normal I am sure I will be used to it no time.

    Would this be because of the chain, or is something else going on?

    I had asked if they were going to upgrade the firmware and he said they only do it when they really need to, and the computer didn't say anything so they weren't going to. Nothing is noted about an update on the service description...

    And finally the tension on the chain is strange... No slack around the sprockets but WAY more play on the bottom of the chain, in fact it can touch the bottom chain guard no problem (it was never that loose before).

    Anyway, just hoping for some info or if I should take it back in...anyone else notice anything like this?
    #1
  2. Bubba Satori

    Bubba Satori Finding my way home

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    Take it back. The chain should not be touching the guard.
    #2
  3. TastyPants

    TastyPants Harasshole

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    I was thinking I could try and adjust it myself, but is the riding differently something to worry about? Would the chain cause this?

    Sigh, I probably will just take it in in the morning...
    #3
  4. dsrydr

    dsrydr Been here awhile

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    Are you sure they put the right sprocket (s) ie same number of teeth, on the bike?
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  5. TastyPants

    TastyPants Harasshole

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    Well no, the part numbers seem to be right but that doesn't mean its whats on the bike...

    27 71 7 708 479: Sprocket
    27 71 7 726 616: Sprocket wheel set

    How many teeth are they supposed to have?
    #5
  6. ShadySmurf

    ShadySmurf Does Own Stunts

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    16/42 Is stock.
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  7. TastyPants

    TastyPants Harasshole

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    Just checked and sprockets seem right. 42rear 16front...
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  8. JRWooden

    JRWooden never attribute to malice...

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    I never heard the term "Judder Damper" before but started thinking maybe it was European ...
    A google search for the word "judder" kinda implies that it is used like the word shimmy or shutter.

    .... but I've no clue that we had something on our bikes that were a damper for anything like that....:lol3

    Ask the mechanic to point it out to you on the bike ? :wink:
    #8
  9. TastyPants

    TastyPants Harasshole

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    Haha, well the description at the top mentioned a belt check as well, but the part description seems to amount to a rubber bushing. A 70$ one at that...

    I'm going to give them a ring and see what they have to say then bring it in or adjust the chain myself tonight.
    #9
  10. Bayner

    Bayner Long timer

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    He's probably talking about the rubber inserts for the cush drive in the rear hub. They go for a pretty penny if I recall as well. Hard to believe you'd have worn out a set that quickly though. I've got twice the mileage and mine still look fine. (You'd get a smoother tip in throttle feeling now if the old ones were pooched).
    #10
  11. itsforrest

    itsforrest Ugly bag of mostly water

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    The repair manual does refer to the rear sprocket carrier as a judder damper. From how it is described in the first post, I wonder of the mechanic is talking about just worn or damaged rubber pieces or if the metal cracked. I can't imagine how it would have broken beside being defective.
    #11
  12. itsatdm

    itsatdm Long timer

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    According to the manuel the chain should have 35-45mm of slack, as measured with the bike on its sidestand with no load on it. The manual doesn't address it, but the way I do it, is to put the bike in gear and roll the bike back to get the slack out of the top of the chain and measure at the bottom. You should measure again after some miles as a new chain will lengthen a little with some miles on it.

    There was a service computer program upgrade for older bikes that did away with some of the snatchyness at low RPM, but it should be on your work order.

    They may have also adjusted your throttle cable to remove any slack, that also helps to smooth things out. If too tight, turning the handlebar all the way to the left will increase rpm.

    I would double check if they meant the rubber shock absorbers or the casting itself, the latter could be dangerous. I doubt if they replaced the casting as that would require ordering the part if they are a typical shop.
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  13. JoelWisman

    JoelWisman Long timer

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    The "judder damper" is the rubber damper that connects the rear sprocket to the hub and damps chain lash.

    The damper rubber does not mearly wear, but also cracks and breaks.

    The quickest way to break the judder damper is to adjust the chain too tight.

    When properly adjusted to factory specs using the factory procedure, the chain will touch the chain guide on the bottom when light pressure is applied to the chain with the bike unladen, preload normal, in neutral, resting on side stand.
    #13
  14. TastyPants

    TastyPants Harasshole

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    Thanks Joel, so perhaps it was adjusted too tight the last time which cracked the damper. It still seems a little too loose on the bottom of the chain. It definitely moves more than 35-45mm which is what the sticker and manual say. I will see what they have to say about it anyway.

    Any ideas on what could have caused the snatchy throttle to go away? It isn't just a slight difference? Could it have been the chain was just too tight before?
    #14
  15. ShadySmurf

    ShadySmurf Does Own Stunts

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    Is that the four blocks inside the rear sprocket that come out when you pull it off, or is it one piece?
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  16. JoelWisman

    JoelWisman Long timer

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    Yes, the "judder damper" is BMW speak for "4 blocks of rubber" inside the sprocket carrier that are often broken into 8 pieces lol.

    As for precieved snatchyness reduction.....

    As is stated by others, throttle cable adjustment has a big impact on this, as do the judder dampers themselves.

    I'm surprised the judder dampers were replaced under warranty since they are considered a wear item, I think.

    Did they replace your air filter? That can have an effect.

    Depending on what software revision you had, an update can change the character of the bike, but it takes a long time to do this. I can't see a shop doing it without charging for the time or even noting it, unless your software was so old their GT1 couldn't communicate with it, in which case BMW pays for the labor.
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  17. TastyPants

    TastyPants Harasshole

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    No I definitely paid for the Judder replacement parts and labor...even though it was their last chain adjustment that probably caused the issue. They did the 6k two or three months and I have been checking the tension since it was fine.

    They did replace the air filter but no software revision was noted on the sheet.
    #17
  18. MikeMike

    MikeMike Long timer

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    Check to make sure the air filter isn't one of the ones that collapses.
    It is worth it to take off the cover and see if it is sitting in the bottom of the air chamber with a torn side lip on the filter (the tear lets it fall or "collapse").
    #18
  19. JoelWisman

    JoelWisman Long timer

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    Since the dealer did both chain adjustments and the tension is significantly different this time, I would definantly have a conversation with the service writter.

    I would start by asking them "why they checked the judder damper at 12k"

    If they say "because the chain was too tight". Well, you get the idea.

    Good luck.

    Sorry for your experience.
    #19
  20. ShadySmurf

    ShadySmurf Does Own Stunts

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    Just for future reference, if those are broke, which I don't see it as a problem if it's just the tab between the two pieces if you are careful putting them back in the sprocket...You can get them HERE for 20 bucks. No affiliation, I just found the place when I had a broken one and started looking. It's way cheaper than the 70 bucks that the dealer would charge, and not like it is hard to put in.
    #20