Honda CB750 Sandcast

Sealing Case Halves

Wayne · 3 · 1946

Wayne

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Looking for something published from Honda regarding sealing the case halves. Decided on my sealer type (Permatex MotoSeal 1 - Ultimate Grey) and I'm ready to get these case halves re-acquainted with one and other again! :)

About the only thing I can find is this drawing and it seems like overkill to me. I just don't see the sense in putting sealer around the main bearing bosses.  ??? To me, that just adds risk of contamination to to the oil system or fouling up a main bearing.  ??? The oil isn't going to leak out anywhere from there and I don't buy the "even pressure" stuff on the case when you torque it. Those cases in the main boss area are coming together when they are torqued, sealer or no sealer as long as it hasn't already started to dry.

I see more of just a perimeter seal being all that's necessary covering all of the external leakage areas. Am I out to lunch on this one?

And a day later I had a thought.  :o I suppose oil could seep down the bolts if there isn't a bit of sealer on the main bearing boss mating surfaces???
« Last Edit: June 11, 2013, 02:13:12 pm by Wayne »
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hondasan

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Oil WILL seep down those bolts unless the mating faces are sealed - just as they did in the factory.

I also put some threadlock on the cylinder head / cam bearing studs (the ones at the front corners of the carriers), as those threads are tapped right through, and can weep oil unless sealed.

Cheers - Chris R.
Chris R.
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Wayne

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