Calling JVB (Jim) 1250 shift cam boxer internals question

Discussion in 'GS Boxers' started by Jontaff, Sep 15, 2019.

  1. Jontaff

    Jontaff Been here awhile

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    Jim,

    Sorry to put your in the spot light, but you know a great deal about these engines than I do, so do you know what the shift cam mechanism (black solenoid) is made out of and it's durability?

    Thanks,

    Jon
    #1
  2. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    :-)

    I can't say about durability, but the mechanism is a combination of plastic casing, metal base and hardened steel pins. I can only assume they will be decently durable.
    [​IMG]
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    #2
  3. Jontaff

    Jontaff Been here awhile

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    Jim,

    Thanks for the quick response.
    I did see those pictures on your thread but I only got the new GS a couple of weeks ago (traded the RT and before that that the GSA) I was concerned about the "life span" on that particular part.
    It will be interesting when you do more work on the engine as to how "the internals" are holding up. I hope the cams wear better than some earlier water boxers.

    Lastly, I appreciate your knowledge and helping the folks out here, including me.

    Jon.
    #3
  4. Jontaff

    Jontaff Been here awhile

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    Nice pictures.
    Do you re-use the valve cover gaskets if they are OK after the valve check?
    #4
  5. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    The valve cover gaskets are completely reusable so long as you clean the surfaces well.
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  6. Bikerboy108

    Bikerboy108 Pat from Jersey

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    yes unless you are the dealer and want to add another $80 + dollars on the bill !!!
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  7. Rider2

    Rider2 Been here awhile Supporter

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    That's $80 each side
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  8. Jontaff

    Jontaff Been here awhile

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    Thanks Jim
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  9. tentative_rider

    tentative_rider Wanna Be On Gravel

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    Out of curiosity, what things move when the shiftcam engages, I can't wrap my head around it.

    TR
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  10. Lead Wrist

    Lead Wrist More Gelände less Straße

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    The cam that controls intake valves moves left-right by the actuator thus different lobes engage to open/close the valves:
    #10
  11. atwoodtja

    atwoodtja Been here awhile

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    BMW is using this same technology in the boxer and inline engines. Pretty big risk for them as a company if they weren't sure it was durable in the long term.
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  12. Jontaff

    Jontaff Been here awhile

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    Thanks for confirming that. I was advised by a friend the other day that this technology was used in the IL engines.
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  13. adventuro

    adventuro Adventurer

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    What keeps the cam in one position or the other. wouldn't the pin that shifts the cam have to retract almost instantly. Looks like maybe I see a third pin or dowel that remains in a extended position to engage one of two grooves.
    #13
  14. Rider2

    Rider2 Been here awhile Supporter

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    Here's a video that explains how it works on the SS 1000 RR. The relevant part starts at 1:40. I'm sure it's functionally identical on the R 1250s. Yes, it happens in a fraction of a millisecond, and the narrator says "it just sits there". There may be something encouraging it to do so, like a soft detent, but I've not seen anything suggesting that.
    #14
  15. adventuro

    adventuro Adventurer

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    Thanks for video, still just hard for me to imagine that it just stays in position...sure looks that way though.
    #15
  16. hammick

    hammick Long timer

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    Yeah and good chance some dealers would charge for gaskets and use the originals.
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  17. chris73

    chris73 Been here awhile

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    It looks like if there was a failure, it would just fail in the last position. Like if the solenoid failed. As long as the cam stays on one side or the other, it should get you home anyway. If cam started floating that would concern me. Like left to right.
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  18. Lead Wrist

    Lead Wrist More Gelände less Straße

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    At 1:32 the narrator is using "soft" and "hard" cam expressions? I'd like to think that doesn't mean what I'd think that would mean - cam hardness is a rather sensitive topic... :D
    #18
  19. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    There are two pins. They retract when the bike is off.
    [​IMG]
    #19
  20. adventuro

    adventuro Adventurer

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    Thanks Jim, I see that in the video, but it looks like something would have to keep it from drifting left/right. This question has kept me up at night....and I don't even own one....yet!:lol3
    #20