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

[Nurse Julie]

I was talking to Trigger about the mess he cleaned up for me in the 3 combustion chambers that had sustained damage. Most of the damage was caused by detonation as we know (Wrong, see note below !!!). He also found fragments of the broken rings embedded in the alloy, which he was able to pick out.

I have circled some of the holes left after the ring fragments had been removed from # 3 & 4. In real life the holes are actually very small.

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And if you look closely at the original photos, you can just see the penetration holes amongst the rest of the carnage.

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[Johnwebley]

   I am surprised,previously any piston that has had ring damage were the ring has escaped upwards and got caught
in the squish band locks like the heads that you have not marked .

 most of my previous experience has been with small 2 strokes,but I did have 1 pot do that on the Honda

[Nurse Julie]

   I am surprised,previously any piston that has had ring damage were the ring has escaped upwards and got caught
in the squish band locks like the heads that you have not marked .

 most of my previous experience has been with small 2 strokes,but I did have 1 pot do that on the Honda

You are totally right John, I wrote that wrong. This is all broken ring damage, not detonation  damage silly me 
Edit....I was trying to do 3 things when I wrote the above, thinking, breathing and standing up.I seem to have lost the art of multitasking 😂😂😂😂😂
Hairy don't you dare say a word 😢😢😢😢😢

[SteveW]

There is a head off a 550 currently on Ebay with the same damage, but only on #2.

[Nurse Julie]

There is a head off a 550 currently on Ebay with the same damage, but only on #2.

I would have been a happy bunny if only 1 of mine had damage instead of 3 !!!!

[mike the bike]

No you wouldn't.

[Nurse Julie]

No you wouldn't.

True

[Nurse Julie]

Finished assembling the bottom end today.
First to go back in was the camchain tensioner. Here is a photo showing all the parts

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The push bar has 1 flat side which faces upwards and the tensioner adjusting bolt pushes on to this to lock it. At the other end is a flat pad which sits on the horseshoe. You can see on the assembled parts a little raised bit on the top of the pad which also shows which way up it needs to be to get the flat side of the bar sitting in the correct place.There are 2 springs that go over the push bar. The horseshoe has 2 bolts holding it in situ and a bit of thread lock was put on as suggested by Bryan, as he has seen these come undone before.

The outer adjuster with the locking nut

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This photo shows the tensioner in the locked position and will be adjusted when the top end is all in place and the top mark showing the push bar is facing the correct way. You can see the pad that goes onto the horseshoe.

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The casing then had the lightest smear of Honda Bond applied, also to the outer sides of the oil seals. The primary chain is in situ on the drive sprocket. There is only the primary chain holding the drive sprocket in place at this stage, hence it's funny angle as the drive shaft is inserted after the cases are put together.

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[Nurse Julie]

The other case had bearing guard applied to the shells. No, that's not a crack across the chain guard, it's a piece of cotton from a rag !!!!

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And the cases were put together, not forgetting the dowels and bolted and torqued.

The Primary shaft was then put through the side of the casing, through the circlip, the bearing, the other circlip, through the drive sprocket hub, through the drive sprocket and the collar and through the circlip, the bearing and the other circlip and out the other side. Another collar was put over the shaft, the cog was put on the end of the shaft. Finally the Primary shaft lock washer was installed with 'OUTSIDE'.....facing outside !!!.

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You can see the new head stud in place replacing the one that had to be mullered to get out.

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You can see on the photo the kick start mechanism I installed the other day. And the advance/ retard unit has been put back on.

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I have a couple of bolts missing from the top casing at the front. I can only think that there were Allen bolts fitted, so I will replace with the correct ones.

[Nurse Julie]

NOW............the most amazing thing, the head has been skimmed. He says it was my nagging that made him do it but I think it was the promise of bacon and onion suet roly poly that encouraged him really .

The dotted lines show the most skimmed area and Trigger says this is quite common as it heats up more on #2 & #3 more than #1 & #4.

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And..........the front brake disk has been skimmed also. The front face of the disk was as flat as a witches tit, the backside was like a roller coaster. I hope all this will stop the squeak !!!!

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[Johnwebley]

not just stop the squeal !!

  but stop the bike !! and you

[Nurse Julie]

not just stop the squeal !!

  but stop the bike !! and you

Ah,yes, that as well John ☺☺☺

[Laverda Dave]

I've only been away a couple of days and I when I return I find you've nearly completed the bottom half! Well done Julie, it's looking good, barrels and head on for Christmas?
Personally I love a bit of brake squeal, it wakes up the box driving morons who frequent London's clogged roads whilst on their mobiles, driving their 4x4's and oblivious to anything around them!

[Greg65]

Julie, thank you for such an informative and detailed series of post's.  I have spent the last 18 months tinkering with my GS 1000 and now turning my attention to my 400. Your blog is really inspirational and I am currently reorganising my workshop before I put spanner to bike. Now I must return to page 6 and read the rest.

Happy bolting to one and all.

Greg

[Nurse Julie]

I am still finding the manuals very lacking. I'm using a combination of both Haynes and the proper Honda Shop manual. These manuals are OK if you have the basic mechanical knowledge needed for the job but for a complete novice numpty like myself, I have to make a lot of assumptions and use my imagination.