Don the Honda I had taken the Ratchets head, 10mm size, the ratchet we know are square. Since this is 5 corner, looks of the Pan bolts they may be 8mm -10mm, the site posted. does not say, but 12-14mm which is of the 2009 or 2007 I own.
I have a few keys that size around, but will take time to find?
lets go with not sure this size , it is not metric, it is a 1950's tool I say 3/8th if you asking me to guess
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