Yamaha RBX 200F truss rod key?

Discussion in 'Hardware, Setup & Repair [BG]' started by Hypercaffium, Apr 18, 2019.

  1. Hi,
    a friend of mine gave me this vintage fretless bass. It looks and plays ok but need a proper setup. I was investigating the truss rod access hole and honestly I can't understand which kind of key I need. I've made a quick search both here and on Google and found inconsistent/contradictory infos. Here's a pic of the truss rod access hole.
    Thanks for your help.
  2. hotbass57


    Nov 27, 2011
    I had a RBX260. I would unscrew the plastic guard and take it out to adjust the truss rod. I used a 4mm allen key with extended length. Got one at hardware store for a couple bucks.
  3. I'm not sure that the plastic guard should be removed, there's plenty of space to operate imho. Anyway, the truss rod hole on this bass is different, I guess I need a key like this:
    Not sure about the size, though.
  4. hotbass57


    Nov 27, 2011
    Huh mine was a regular allen key. Like this. [​IMG] just one end a little longer. The cover came out it was easier to get wrench in. Is the end not clogged or painted?
  5. If you look at the picture, that's not a hole. I don't see any paint there, just a black nut.
    It seems an hexagonal nut so I guess I should use the same tool I used for Gibsons, but I'm not sure about the size. I'll try some or the tools I have at home.
  6. I confirm it's a 8mm nut. I used an 8mm key I have at home and it worked. I needed to remove the neck to operate but I was able to set it straight finally. I think a Gibson 8mm key would work perfectly without removing the neck.
    I moved to string saddles and realized that I don't have a proper key. It's time to search... again.
  7. Phoenix369


    Dec 24, 2020
  8. Phoenix369


    Dec 24, 2020
    You're high if you think it's 8mm. I just tried it. 8 is way too big.
  9. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    According to Yamaha, it's a 5mm wrench.
  10. Phoenix369


    Dec 24, 2020
    Took it to my guitar tech tonight. It's a 5/32.

  11. You might be careful with that. I’d expect a Yamaha to be metric and 5/32” is slightly smaller then 4mm but if you have to apply more then minimal torque to the truss rod nut that slightly smaller could cause some problems.
  12. Jefenator

    Jefenator Supporting Member

    Aug 22, 2008
    I've had a few Yamahas with this setup. I got a suitable key from the hardware store (8mm sounds right...) and ground the short end down so I could use it without having to remove the neck.
    They might have included such a key with the basses when they were new - that is quite clearly why there is a rout with a little plastic cover.
    I do take the plastic cover out to keep it from getting scuffed up by the hard metal key. It's a bit tedious and inelegant - but better than having to remove the neck!
  13. Maybe yours is different, I don't know. I don't have that bass at home anymore.
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