CB466f

[Erwin83]

I get why the lapping-stick is frustrating.. pfff.
Anyways, in the end I found a rhytm and got a nice silver finish on the valves and seats.

Even more frustrating is forgetting to fit the valve guide rubber seals, and having to fit 12 valves instead of 8. Especially without the right tool for it.

Anyhow. It all worked.
Fluid level was nice and stable after doing the leak test again.

Thank you all for the advice given!

[Erwin83]

Just picked up the cylinders. Now it's getting real 

[Nurse Julie]

Looking good 👍👍👍 A question, why have you got brass screws on the manifold rubbers? Will the brass not be too soft to get a decent tightness to avoid air leaks?

[Erwin83]

Looking good 👍👍👍 A question, why have you got brass screws on the manifold rubbers? Will the brass not be too soft to get a decent tightness to avoid air leaks?

Well, simply because I had to destroy the original screws when replacing the rubbers, and I inherited a bunch of very pretty high quality brass bolts from my Grandfather who was a fine instrument maker (not the music stuff, but metal working). The right size was available.

The tightness is no issue at all. It's 'normal' tight. There are 15 turns of thread in use, so not worried about that.
I guessed the advantage of using softer screws (instead of hex-bolts from the DIY store) is the possibility to get the bolts off again without destroying the cylinder head, should it ever be needed in future. Less risk of damaging thread or getting corrosion.

[Nurse Julie]

Fair enough.... Your Grandad would be well pleased I'm sure.

[Erwin83]

For the record, the machinist has decided to use the Honda spec, as the pistons (according to him) are similar to the original material, and not forged like on high(er) quality tuning-pistons such as mahle etc.

He measured all pistons before boring and concluded that all 4 pistons had exactly the same size. Therefore, he ended up boring the 4 holes at the same size too.
Checked the piston ring gaps, were good too. All-in-all, he was quite impressed with the quality of the Forseti kit.

I paid 315 euro for the service of boring / honing and checking all measurements. A bit more than I expected.
Together with the Forseti kit and a gasket kit for the engine, I will be in for 600 euro + oil and filter.

[K2-K6]

Certainly appears that you've had decent work completed to build it with the big bore kit,  hopefully you'll have good results. Interesting to hear how you get on.

The brass screws are an interesting subject when used with these engines.  For corrosion purposes they are worse than the original materials (zinc plated steel) as brass exists at a greater distance away from aluminium casting than does zinc. Also the brass will effectively corrode / scavenge from the aluminium casting,  where the original materials won't. This is often seen when carburettors are left to corrode,  the brass components "eat" the predominantly zinc castings. 

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Above chart is from this site http://www.corrosionpedia.com/an-introduction-to-the-galvanic-series-galvanic-compatibility-and-corrosion/2/1403 which discusses this subject.

Like many of the Honda design of that era,  there are many very small but concise details which attract no immediate attention but are there nonetheless and impact the overall construction unseen.  Very clever, those Japanese development engineers 

[Nurse Julie]

I'm pleased you explained that Nigel.... My only offer was to inform Erwin that if he wanted the proper ones as fitted by Honda, I have no doubt we will have them in stock.

[Erwin83]

Wow, that’s a good ring of the bell. Thanks for that.
You made me google this for some more background and I see now that this is not a smart choice at all. Although real issues are more expected in a wet environment, which this isn’t really, I will change them out nonetheless.

What is the preferred material for exhaust taps? I always thought people used brass. Or is it copper? Or s my memory failing me completely?

[Trigger]

Just picked up the cylinders. Now it's getting real 

They don't look like std head studs ?

[Erwin83]

No, they’re the upgraded Zebra style.

(a previous owner painted the engine without dismanteling, this is what you get)

[taysidedragon]

If a low grip threadlock or coppergrease is used on the threads would that stop any corrosion altogether or just delay it for a while?

[Erwin83]

Installing the cylinder is quite tricky without the tapered bottom of the cylinders. But after an hour on my knees next to the bike and many drops of sweat later, the block finally thumped on the new gasket (which I gave a lick of liquid gasket too, just to try and prevent leaking for as long as possible).

[Nurse Julie]

I keep my fingers crossed you have no leaks. That area is quite oil free really, its just the area around the oil return paths / dowels / studs, that usually leak if anything. I can see this bike being back on the road by Christmas, you are making great progress 😊😊😊

[Erwin83]

That may be possible, but once the engine is back together, I also have some wishes with the exhaust. I currently have a 4-2 based on the original header pipes of the 350f. I have the ambition to make it 4-4 again with 4 open peashooters.