CB400/4 ENGINE STRIP, ASSESSMENT AND REBUILD BY JULIE - NOW COMPLETE

[Nurse Julie]

That's bad Julie,
Tool hire and workshop space charges - Trig offered me overnight accommodation for next years C90 trip to Deutschland - unfortunately not passing your place - but he didn't mention CHARGES 🤓
Looking forward to seeing inside the motor,
Ian

He just sends the invoice later 
Come on Julie the top end should be off by now.

The top end is almost off Paul. I have the rocker cover off, camshaft out and just started on the head bolts but I have got stuck on one of those nuts right down by the spark plug port, I just can't get it to move. I will have to wait for Trig to come back as I'm worried I will muller it, so need his input. I can't progress further with the head bolts as it says remove them in sequence....so I'm doing some ironing instead  I will give a proper update later wish some pics. (On the engine that is, not the ironing  )

[paul G]

No not that bothered about seeing you iron Triggers undies

[Nurse Julie]

Drained oil, no metal debris on the magnetic sump bung. Removed all cables and ancillaries and got stripping.
You can see the oil jet tubes sitting behind the camshaft. 
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Each is a different diameter and you can see the supporting grommet on the left one is broken.
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When I unscrewed the hex bolts securing the cam chain tensioner holder, I was expecting it to spring up because that’s what it said in the book but there was no upward spring because the tensioner slipper was seized in the down position. I loosened off and fiddled with the tension adjuster at the bottom front of the cylinder block and hey presto, the slipper popped its head out of the tunnel.
The cam chain has a minute amount of movement on the cam sprocket but nowhere as much free play as I was expecting.
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[Nurse Julie]

Oil jets from the head.
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The head bolt on the left side down in the spark plug port was an absolute pain. I tried to undo it but could feel the socket slip off the nut. In the end I got Trigger to have a go and it took him over an hour of trying with all different tools, hitting, smacking, drilling and eventually it came off, in many parts. As a result I now need a new head stud. It was probably my fault in the first place as I didn’t clean all the old dirt out around the nut head and rounded it off a bit with the first turn of the socket !!.
So far I have found all genuine Honda gaskets and Honda pistons with original internal nuts and bolts so even though I said I think the engine has been apart before, Trig reckons it may not have been. Won’t know for sure until I get the cam chain off to see if it’s a soft link that someone has changed in the past to confirm if it has been apart or not.
I have left everything on the strip down bench for now but need to have a good clean up and inspection of the cam shaft / followers / valves / springs etc to see if there is any undue wear that needs attending to. There is nothing jumping out at present that looks bad or broken and it all looks in very good order to me, nice and clean and no rust.

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[Nurse Julie]

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The mullered head stud
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So, problems I encountered today.
I can never seem to lay my hands on the correct size spanner or socket, even though I seem to have hundreds out of the tool box !!
I do find it difficult undoing some of the very tight nuts and bolts, but managed them all except the one on the head which I needed help with.
I have to make my own cuppa's.....I always make him Tea when he's working !!
And.....the workshop now looks like a bomb has hit it and I have been told in no uncertain terms to clear it up.

Now, I have to think what I'm going to cook for dinner 

[mike the bike]

That head stud looks like it's corroded in. 

[Nurse Julie]

That head stud looks like it's corroded in.

Yep, that's one of the next problems Mike, how to get the blighter out. I know Graham has these special stud removal thingies, so I will have a play.

[Nurse Julie]

A few more general pictures
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[orcadian]

Looks like a really well cared for unit - the cam journals look like new and the cam will live to fight another day.  I usually dunk the piston crowns in cellulose thinners over night or even longer and the carbon just rubs off with a cloth, same with the valves when you do those.
I had a stud like that one a few years back and waited till the cases were separated and empty, then heated the general area (not too concentrated in one spot) and put the whole stud length in the vice lengthwise and screwed the case off the stud - there were 3 like that and all came away without damage (studs were knackered of course!)

Ian

[yozzer74]

Great job keep it coming 

[Oddjob]

Seems to have been running rich, carbon should be a sort of biscuit brown BUT that was in the days of leaded petrol, might not be the same with unleaded.

I'd check the rings, there appears to be some blow past the rings as the piston skirts show burning. Area between top and middle ring has carbon on it, more than there should be and the gap appears quite large in the ring. I suspect it may need a new set of rings.

The cam followers look a little stepped, ask Graham to have a look at them as it might just be the light. Cam journals look really good, not a great deal wrong as yet.

[paul G]

And.....the workshop now looks like a bomb has hit it and I have been told in no uncertain terms to clear it up.
 
Having seen his workshop I bet he has.

[Nurse Julie]

Seems to have been running rich, carbon should be a sort of biscuit brown BUT that was in the days of leaded petrol, might not be the same with unleaded.

I'd check the rings, there appears to be some blow past the rings as the piston skirts show burning. Area between top and middle ring has carbon on it, more than there should be and the gap appears quite large in the ring. I suspect it may need a new set of rings.

The cam followers look a little stepped, ask Graham to have a look at them as it might just be the light. Cam journals look really good, not a great deal wrong as yet.

Thanks Ken. There are no steps on the faces of the  followers, it's just the photo. I have seen steps on the engines Graham has in that big, it would be like jumping off a cliff for an Ant😁. Graham had said the rings had probably had it as the engine had too much crankcase pressure and oil and smoke in the airbox. I was going to fit new rings anyway but will see what the bores measure as may need a rebore and new rings.

[Nurse Julie]

And.....the workshop now looks like a bomb has hit it and I have been told in no uncertain terms to clear it up.
 
Having seen his workshop I bet he has.

No Paul, I'm in the dirty workshop, not the inner sanctum of the engine building room !!.

[paul G]

And.....the workshop now looks like a bomb has hit it and I have been told in no uncertain terms to clear it up.
 
Having seen his workshop I bet he has.

No Paul, I'm in the dirty workshop, not the inner sanctum of the engine building room !!.

is he being a bit petty then