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zinc-plated steel bolts okay for application: skidplate f650gs?

Discussion in 'The Garage' started by landSurfer, Jan 15, 2018.

  1. landSurfer

    landSurfer Adventurer

    Joined:
    Nov 13, 2017
    Oddometer:
    47
    Location:
    San Diego
    I bought a used Ricochet skidplate and hope to mount it to my f650gs twin 2009. Didn't come with mounting hardware and BMW wants $$$ for theirs, so would love to NOT give them that unearned cash.

    Coupla questions for the braintrust here:
    - another inmate directed me to McMaster-Carr for their MUCH less expensive anti-vibe mounting studs here. Q: Wondering if they're the same dimensions as BMW's (some others here have used them, but may have cut them to size)
    - Related to this, I'm looking for an online source of actual dimensions for BMW's OEM mounting hardware (I've found fiche illustrations but no dimensions); anyone know of a good dimensions source?
    - Wondering if McMaster's mounts, being zinc-plated steel, will be okay re: mixing dissimilar metals (they will thread first thru the aluminum skidplate, then into the engine sump).

    Thanks in advance,

    -j
    #1
  2. tbas3

    tbas3 Been here awhile

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    I would not worry to much about dissimilar metal corrosion unless you plan on riding a lot in salt or regularly dipping the bike in seawater.
    #2
  3. the_gr8t_waldo

    the_gr8t_waldo Long timer

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    you'll not likely find the fastener sizes other then by measuring the plate for yourself, the bmw fiche will indicate the fastener head/style. mixing metals wil not be an issue. most any fastener that you can find will also be available in stainless( a much better looking metal than the blue flash that is zinc electro plating, or hot dipped , imho) cutting bolts isn't all that hard( just tedious) so I wouldn't be overly concerned with over length. I would use nyloc stop nuts WITH blue thread locking chemical.
    #3
  4. Trailrider200

    Trailrider200 Long timer

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    aluminum and steel are not dissimilar for corrosion. any corrosion is what the sacrificial zinc is for. anti-seize the bolts.
    #4
    Bigger Al likes this.
  5. nbsdave

    nbsdave Been here awhile Supporter

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    Jul 26, 2012
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    sarasota, fl
    if all you need are bolts
    just hit the Ace Hardware and grab some stainless bolts/nuts/washers. Or use nylon lock nuts.
    I just don't like zinc plated.
    #5
  6. landSurfer

    landSurfer Adventurer

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    Thanks, all. I've got what I need here. Sure appreciate it...
    #6
  7. kantuckid

    kantuckid Long timer

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    If by "dissimilar metal corrosion" you actually meant galvanic action, no salt is required for that to take place...:lol2
    #7
  8. tbas3

    tbas3 Been here awhile

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    Dissimilar metal corrosion is a term we use in my line of work. While you are correct no salt is required for it to happen it will greatly increase the rate at which it happens. You can get away with a lot on a plane that lands in fresh water. Put the plane into salt water and the rate of corrosion will go up. For normal motorcycle usage you can get away with the cheap zinc plated hardware. If you like to ride in the winter like some do the salt makes his choice of hardware more important.
    #8
    kantuckid likes this.
  9. flei

    flei cycletherapist

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    imo, this is NOT correct in this particular application. you should use the rubber isolators; if you do not and the skid plate is bolted directly to the engine case, if you get a hard hit on the skid plate it may shear a bolt, or worse, break the case. also, as far as i can tell, the MM-C parts are identical to the stock bmw parts (i am on my second set of them). and yes, it is a good idea to put anti-seize on the threads where they screw into the case so if/when the rubber shears off and you need to replace them you can more easily get them out.
    #9
    Boatman likes this.
  10. landSurfer

    landSurfer Adventurer

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    I'm with Flei on this. BTW Flei, I passed on your McMaster-Carr (McM-C) tip to Don who makes the Ricochet plates in Utah; he couldn't believe the price compared to BMW's.
    I recv'd your recommended parts today from McM-C (ordered them last night!) and was surprised to note the threaded components on each side of the neoprene bushing move independently of each other. I'd assumed it was a single threaded thru-rod, but not so. So this gives extra fore-aft flex as well as vertical compression. On my low (relative to the f800gs for example) f650GS I'm losing clearance by putting on the skidplate, so expecting more dings and so I'll buy some extra bushing-mounts for backup from McMaster-Carr.

    Man, I'd love to see a MM-C option for every one of these expensive lil' BMW parts; what a useful spreadsheet that'd be for many of us!
    #10
  11. flei

    flei cycletherapist

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    I also have an f650gs (twin) with the Ricochet skid plate. I have ridden it for 5 years (about 35K miles), and it has taken quite a few very hard hits. Twice i have bent the plate a bit and sheared off a couple of the rubber mounts, but the plate has prevented any damage at all to the bike. IMO the Ricochet plate has saved my ass and is a bargain.

    I also have often bought replacement hardware for the bike from MM-C if the bmw parts were over-priced, which they often are. i find that the A & S Cycles parts fiche is the easiest place to check out what you need (https://www.ascycles.com/BMW-Motorcycle-Parts-Fiche). I also do buy from A&S since their prices are less than most BMW dealers and there is no charge for shipping with no minimum, and they ship fast. I highly recommend them.
    #11
    landSurfer likes this.
  12. ericrat

    ericrat Long timer Supporter

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    I wouldn't want a skidplate without the rubber isolation dampeners.

    Max's site is great for pictures. http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=55255&rnd=07242017

    The parts fiche lists the isolators as M8

    Here is a picture with a ruler, again from Max's site.

    http://www.maxbmwmotorcycles.com/fiche/NotesParts/11117682158_3_B.jpg

    Something like this might work.

    https://www.mcmaster.com/#rubber-isolators/=1b6pj2e

    It is too darned cold out to go outside and remove my skidplate to measure!
    #12
  13. chasbmw

    chasbmw Long timer

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    A cheap thread gauge is invaluable, tells you what diameter the bolt is and the thread Pitch.


    Sent from my iPhone using Tapatalk
    #13
  14. ohgood

    ohgood Just givver tha berries !!!

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    use anti-seize or loctite.

    that's wayyy too much wondering/worrying for a skidplate fastener.
    #14
  15. ericrat

    ericrat Long timer Supporter

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    Not when the only mounting on the skidplate is into blind, threaded holes in the engine case.

    This thread might be better placed under Parallel Universe. http://advrider.com/index.php?forums/parallel-universe.77/
    #15
  16. ohgood

    ohgood Just givver tha berries !!!

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    OUCH that's a dumb design. Might better use low strength studs in the case and carry spares.
    #16
  17. H96669

    H96669 A proud pragmatist.

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    Ok
    I wonder? Same seized up/broken and degraded rubber parts I had to extract from my friend's 05 1200 GS?Wasn't exactly easy but replaced with same BMW part$.However took care of the BMW mounting that took 3 wrenches of different sizes if just to remove that skidplate for a simple oil/filter change.:lol3
    #17