Topic: Oversized hole on CB750 crankcase

[Holiday]

Putting together the crankcase both my parts fiche and the bolt set I bought indicate that the center bolt hole (pictured below) takes an 8mmx56mm bolt.



However the hole is clearly 10mm wide, it needs a 10mm bolt. I'm trying to figure out why everything points to that hole being 8mm when in reality (at least on my crankcase) it requires a 10mm bolt. Any ideas why? Could it have been bored out? Too I checked my old bolts and couldn't find a second 10mm bolt. Very mysterious.

[Alan F.]

That's strange, I looked at mine and that hole has the same size bolt as the surrounding ones.  Pics are in my build thread (link in my sig line) if you need a visual. 

Maybe someone had stripped the threads out in a past life and tapped larger?
-Alan

[754]

Is there not a 10mm bolt that holds the stamped metal bracket the holds the carb overflow hoses?

[mystic_1]

I just measured two different K0 cases (an unnumbered case, and #1035047) and both the left and center holes are 10mm and unthreaded, the right hole is 8mm and is threaded.

BTW where'd you get your bolt set?  I already have stainless allens for the side covers but am wanting stainless allens for the upper and lower case bolts.

mystic_1

[Holiday]

I got my bolt sets from http://www.stainlesscycle.com/catalog/. They have top end and crankcase bolts.

So my crankcase is as mystic_1 two examples. My engine is a K2.

[mystic_1]

Sweet thanks for the link.

mystic_1