4th gen carb diaphragms

Discussion in '3rd & 4th Generation 1990-1997' started by bk94si, Aug 6, 2019.

  1. bk94si

    bk94si Insider

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    Has anyone figured out a replacement diaphragm for the 4th gens? I searched and found lots of threads but no answers. I am wondering of any of the JBM products will fit. Or something made for another bike.

    I don't need them now but with a 22 year old bike, I can't imagine they are going to go much further.
     
  2. fink

    fink Member

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    NRP carbs in Manchester have been flogging them for decades.
     
  3. bk94si

    bk94si Insider

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    I'll look again but I didn't see them last time I looked.
     
  4. bk94si

    bk94si Insider

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    Nope. See them for older VFRs but not a 97. Closest I can get is a 93 VFR
     
    Last edited: Aug 6, 2019
  5. JIMLARCH

    JIMLARCH New Member

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    I checked NRP site. It says CALL. Likely a special order requiring your first born as part payment.
     
  6. bk94si

    bk94si Insider

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    I guess I need to look again. I didn't see it at all. Thanks.
     
  7. scottbott

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    I may have been dreaming it but I am sure that I saw something somewhere about somebody getting a new batch made if there were enough people interested, may have been on another forum ???
     
  8. bk94si

    bk94si Insider

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    I looked again and searched a different way and found them. Listed as unavailable but I did send them an email.
     
    fink likes this.
  9. bk94si

    bk94si Insider

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    An email that was never answered.......
     
  10. squirrelman#1

    squirrelman#1 New Member

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    don't worry so much brian, the diaphragms might outlive us all.
     
  11. bk94si

    bk94si Insider

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    I would love to think that but the ones on my Hawk went out at about 24 years old and my VFR is 22 years old now. Realistically, they might be gone in the next few years and I would rather find some and replace them prior to actually needing them than needing some and being unable to find any in a few years.
     
  12. bk94si

    bk94si Insider

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    Sometime soon, I will take them out and measure them. Hopefully JBM will have some replacements available but they don't list by the bike, you need the measurements unless someone has already figured out which fit.
     
  13. squirrelman#1

    squirrelman#1 New Member

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    often, the diaphragms that fall apart have been cleaned improperly/exposed to harsh chemicals.
     
  14. bk94si

    bk94si Insider

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    Not sure I every cleaned them. The first time I took them apart was to install a jet kit and I found the diaphragms had pinholes.
     
  15. Yawk-oh

    Yawk-oh New Member

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    I have a 93 and overhauled my carbs recently: all of the diaphragms appeared to be in very good condition - pliable and springy still. The bike has done 64k miles.

    But like you said, it's 22 years and many things such as fuel quality might accelerate their deterioration. How did you find out that they had pinholes?

    vfrDSC_0762sm.jpg
     
  16. bk94si

    bk94si Insider

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    Held them up to light and could see the light shine through them. The pinholes were in the creases.
     
  17. Yawk-oh

    Yawk-oh New Member

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    Ah, of course. Have you noticed any performance issues with the bike? Granted, the diaphragms will not function perfectly if there are any leaks, so it is probably a good idea to start hunting for new ones.

    I placed an order on a cheap slide/diaphragm/needle kit from overseas, and if it is any good, I will probably order a full set so that I'm prepared for when mine eventually fail. I plan to keep the bike for the foreseeable future, so it probably makes sense to stock up on some wear items that are increasingly harder to find.
     
  18. bk94si

    bk94si Insider

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    Keep in mind this was on my Hawk, not my VFR. No performance issues. I think it would have to be bigger than a pinhole to affect performance. Have a link to the kit you found?
     
  19. Yawk-oh

    Yawk-oh New Member

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  20. squirrelman#1

    squirrelman#1 New Member

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    ^^^ let us know if it works, please.
     
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