Back in the day (and maybe still today?) aircraft guys used silk thread between the cases as a sealer. If it would nt be such a mess to redo in case it doesn't work on the Honda cases...
Just imagine, silk thread from a kamikaze pilot's scarf...
Be careful, when you say these things on the internet some inexperienced person might actually try it and ruin the engine rebuild. They would have to redo it all.
Including taking the engine in or out. Also that silk thread could cause a case to get warped or cracked when the pressure of the case bolts is applied.
Japanese engine cases are very precision and you want the cases to fit tight.
No leaks.
Lucky,
I cannot see why you feel the need to tell me to be careful with what I say. We are all adults here, and I don't see how anything I wrote could bring anyone in trouble. If you dig that deep into an engine, you should know what you do, otherwise leave it to someone who knows.
If you only think for a second about how thick a silk thread is, you would figure out that there would be at no point any danger to the cases. It is just a very old school way of sealer, before there was any chemical replacement. And aircraft cases are surely not less precise than a mass produced motorbike case...
On top of that there is less danger of excess sealer squishing out and clogging oil passages with a silk thread.
So peace, and be open to things you may not have heard of or understand...