Recently, I noticed a missing bolt in the engine case of my (carbureted) 2005 Honda CBF600SA and am a bit baffled as to a) how it went missing and b) what it holds together — can anyone help me pinpoint what the purpose of this bolt is/was and what is "missing"?

Engine case with missing bolt and scratch highlighted

I don't remember noticing that the bolt was missing when I bought the bike, but it has indeed fallen over onto that side (the right side) at least once; Is it possible the bolt came out during the fall? Alternatively, I took the bike to a shop to have the "big" 24,000km inspection (cf. user guide pp. 97–99) done for me; Is it possible that something in the affected area was done ham-fistedly? — There is a scratch on a corner of the engine case right next to where the bolt should be.

  • What is the year/model of your bike? I see it's a 600 (or 599, heh). Sep 25, 2016 at 22:29
  • Added; Sorry about forgetting that! Sep 25, 2016 at 22:30
  • I've looked at about a 1/2 dozen images of the engine on bikes like yours and am not seeing anything there. I was looking at 2007 models, but I don't think there's much difference ... everything else is there. It looks as though the bolt head popped off and left the threaded area behind. That's gunna be fun to remove. Sep 25, 2016 at 22:41
  • Actually, the bolt is completely gone: There's just a hole with threads... Sep 26, 2016 at 6:05

2 Answers 2


I found the original of the below image on Wikipedia's page for the CBF600. It doesn't appear to be anything attached there.

enter image description here

Now that doesn't mean yours did not have something attached there, like an aftermarket cover of some sort.

IMO, what you have identified as scratching looks a bit like corrosion to me.

  • Thanks: This answer was very enlightening even if I'm still somewhat uneasy about the bright silver color of the threads on my engine compared to seen in your photo. However, is it possible that a black cast-iron engine case in fact "corrodes" to such a silver color?-- if so, then you're probably right in saying it's not a scratch but rather corrosion. Oct 2, 2016 at 8:15

Try looking here parts fiche 1

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