Yamaha BB414 truss rid size?

Discussion in 'Hardware, Setup & Repair [BG]' started by Arnold, Dec 31, 2014.

  1. Arnold

    Arnold Supporting Member

    Jan 30, 2002
    PA/MD/New York City
    I just picked up a Yamaha for a spare. Does anybody know what size Allen key fits the truss rod?
  2. T_Bone_TL


    Jan 10, 2013
    SW VT
    Yamaha's usa site only seems to offer a "general owners manual" when you hit the BB414 page. They have a general statement that "newer" basses are 5mm and "older" ones are 8mm - which should be enough to tell apart (since they don't specify when "older" and "newer" separate.) In some cases you may need to shorten a "stock hardware store" Allen key's "short leg" to fit in the truss rod access pocket.