Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: McCabe-Thiele (Ted) on March 20, 2021, 04:46:19 PM

Title: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 20, 2021, 04:46:19 PM
I have seperated the crank case halves - I do not think it has been split before but who knows. A very thin white adhesive that pulls off easily was present. The main bearings are marked D6H-A STD.

Do these look like originals?

The crank journals on the mains look good  - they are unmarked.

Where is the best place to purchase?



.(https://live.staticflickr.com/65535/51055884322_37d959e4f3_k.jpg) (https://flic.kr/p/2kMCKDC)main bearing shell (https://flic.kr/p/2kMCKDC) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr



.(https://live.staticflickr.com/65535/51055819861_6ac38e1281_k.jpg) (https://flic.kr/p/2kMCque)rear of main shell (https://flic.kr/p/2kMCque) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 20, 2021, 06:06:48 PM
Like ken says numbers mean nowt, you need to measure the journals VERY accurately to see what size they are andcross refer to tables in manual
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 20, 2021, 06:28:14 PM
So it's not a straight DS part then!
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 20, 2021, 08:39:46 PM
No, you need to identify the colour used, there are 5 colours for the 400, black, green, brown, yellow and the 400 has a blue that most don't have.

As I previously said, see if any remnant of the old colours are still on the edge of the shell, green shows up pretty well for instance.

Check the crank journals for scoring, with the state of that bearing I'd be worried about the journals, run a fingernail across it and see if you can feel anything.
The journals look perfect IMHO not a groove or anything. No step with fingernail. Be dammed if I can see any colour codes I will look again with a light & magnifying glass. Are the big ends the same where STD does not mean anything?
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 20, 2021, 10:12:07 PM
Big ends may be ok, that damage could be dirty oil infrequently changed but who knows
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 20, 2021, 10:55:09 PM
Looking at the DS site conrod bearings look more available than the mains that are shown as no longer available.

What do you do if they are not available surely someone must make them even if you have to have a crank grind in the process?
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Nurse Julie on March 21, 2021, 08:02:58 AM
Buy the shells from Yamiya Ted if you can't find them locally. You don't have cranks ground on these engines just to make shells fit. This isn't a Ford Anglia 😁😁😁
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 09:10:54 AM
Buy the shells from Yamiya Ted if you can't find them locally. You don't have cranks ground on these engines just to make shells fit. This isn't a Ford Anglia 😁😁😁

PS What's a Ford Anglia is it like  Ford Prefect.
Okay that is good to hear at first glance I can't see any colour markings - I'm not sure if the colour is on the back or the edge of the shells. If I can't find any markings will my caliper tool  be accurate enough or will I need to get them micrometer checked? I've printed of the parts page it only seems to give clearance sizes. There's me thinking STD on a shell meant standard size!
PS A Ford Anglia? Are they a later version of the Ford Prefect😁😁
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 21, 2021, 10:00:03 AM
You need to be able to measure accurately to at least 2 decimal places in metric(0.01mm=0.4thou) so not within verineer acuracy im afraid. May be cheaper to get in done by somebody used to micrometers as the acuracy "feel" is an aquired art
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 10:13:07 AM
You need to be able to measure accurately to at least 2 decimal places in metric(0.01mm=0.4thou) so not within verineer acuracy im afraid. May be cheaper to get in done by somebody used to micrometers as the acuracy "feel" is an aquired art
I agree back in the day depending how hard I tightened the screw changed any measurement.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 21, 2021, 11:00:37 AM
Yup, even with the little ratchet that is supposed to limit the movement
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 11:59:23 AM
TED CMS still sell most of the main bearings, I was wrong as well, there appears to be a Red bearing as well, no blues or blacks but do have Brown, Green and Red. Brown and Green are the most common colours. Click on a bearing and you can see the colours on the edge of the bearing so you know where to look.

https://www.cmsnl.com/honda-cb400f-england_model14639/partslist/E01.html#.YFcwHVX7SUn

No 42 for mains, No 40 for conrods.

Thanks that's good to know - I've looked at the main bearings in the lower crankcase - I can't see any colour markings having checked all 5. With a bit of luck I might have more joy when I check the upper halves/
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 03:11:39 PM
I have re-examined the lower main shells - I have found what might be a colour on one of the shell edges to me it looks like a shade of green?

.

(https://live.staticflickr.com/65535/51058480758_dee9bd3631_k.jpg) (https://flic.kr/p/2kMS4tL)Main bearing shell (https://flic.kr/p/2kMS4tL) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Nurse Julie on March 21, 2021, 03:25:21 PM
Indeed that is green one Ted.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 04:01:16 PM
Whatever you do Ted don't mix the shells or forget where they came from.

As Julie says that definitely a green, so that journal requires a green pair of shells. You could use the back of the shell markings and see if the one you've identified is the same as the rest. They tended to use the same marks for the same colour for the same production run, so if any other shells match that marking it's reasonable to assume that's a green shell as well. The conrod shells use the same method so check the side of those for colours as well.

Good point so far they are all still in the right position but I will record them when I take the crank out - looking at the meaningless codes on the 5 shells they are D6H-A,D6I-A,D6T-A,D6I-A & D6H-A that means they mix the colours on an individual crank bearing. The Green one is D6I-A there are two with this colour journal 2 & 4.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 21, 2021, 04:34:35 PM
They NEVER mix colours on one pin but different colours on different pins is common.
Non of the numbers on the shells mean anything apart from production code, last thing done in production is measure thickness to 0.001mm and colour code them
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 04:47:50 PM
They NEVER mix colours on one pin but different colours on different pins is common.
Non of the numbers on the shells mean anything apart from production code, last thing done in production is measure thickness to 0.001mm and colour code them

I'm learning here I have never encountered a car with such complications as different coded journals on the same crank - wonder why STD didn't mean just that with oversize being +0.1 or whatever.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: K2-K6 on March 21, 2021, 06:03:30 PM
"I'm learning here I have never encountered a car with such complications as different coded journals on the same crank - wonder why STD didn't mean just that with oversize being +0.1 or whatever."

It is, in essence, a view of the lengths they went to in production tolerancing. Ordinarily in most process as it advances the tolerances are accumilative (unless by happy accident one error cancels another) with the accepted machine accuracy and repeatability available producing the components being recognized, the range of 5 different shell dimensions is planned to compensate for that process capability. It effectively pulls all of that production line tolerance back to as close to zero that they could get it.

In terms of "old money" a BMC A series built with en40b crank fully balanced, ground, nitrided, micro polished to perfection,  with rods balanced end to end and rod to rod, etc etc, effectively the best hand finished blue printing only gets close to what these engines came off the production line as absolute standard.  With near 100bhp/litre and usually ten thousand rpm ceiling to go with it, that really shows just how good this design and production was, that's in mid to late sixties and early seventies, there's nothing that came close to them.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Bryanj on March 21, 2021, 06:20:59 PM
In production Honda used air gauges to measure pins and housing which were accurate to parts of 0.001mm and as such could selectively fit parts to get the EXACT design clearance.
When did you ever hear of an "old" car doing 120 000 miles and on stripdown find everything in tolerance and yes i have seen that, chains were shot but all the rest was good enough to refit
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 08:20:08 PM
What journal was the green shell on Ted?

Must be either 2 or 4.

You are right Oddjob the Green Shell was on number 2!

As D6I-A was the bearings on 2 & 4 I guess they are both the same.

I have just removed the Conrods a C is marked  on the front edge two of them have number 2 & 3 on the other side but they were not in the respective cylinder bore so I am thinking this number in black print is meaningless. They were all fitted the same way round as regards the side casing number on the side  "S59" on all four.

Tommorow I will lift out the crank & check for markings on the shells being carefull they do not lift out with the crank. I will then check each bearing for any colour markings and double check the shell codes.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 08:33:52 PM
"I'm learning here I have never encountered a car with such complications as different coded journals on the same crank - wonder why STD didn't mean just that with oversize being +0.1 or whatever."

It is, in essence, a view of the lengths they went to in production tolerancing. Ordinarily in most process as it advances the tolerances are accumilative (unless by happy accident one error cancels another) with the accepted machine accuracy and repeatability available producing the components being recognized, the range of 5 different shell dimensions is planned to compensate for that process capability. It effectively pulls all of that production line tolerance back to as close to zero that they could get it.

In terms of "old money" a BMC A series built with en40b crank fully balanced, ground, nitrided, micro polished to perfection,  with rods balanced end to end and rod to rod, etc etc, effectively the best hand finished blue printing only gets close to what these engines came off the production line as absolute standard.  With near 100bhp/litre and usually ten thousand rpm ceiling to go with it, that really shows just how good this design and production was, that's in mid to late sixties and early seventies, there's nothing that came close to them.

Ah the good old EN40B nitride crank standard in all the S variants 970S, 1071S & 1275S that all takes me back to my teenage days K2-K6 !!
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 10:55:49 PM
Lol, Ted the numbers on the rods don’t refer to the cylinders they are fitted to, it’s how Honda identified the journal size so further down the production line whoever was assembling the engine just needed to check those markings and the letters on the crankshaft to know what colour to fit.

It sounds complicated but once you get your head around it it’s really very easy and logical

At the moment my head is awash with contradiction including the fact that when I split the crankcase it was almost perfect - no bits flying out everything stayed in the top half that was face down except the main bearing to number 5 journal that stuck to the crankshaft - the other 4 stayed in the casing.

Now here is an observation having just had a double Glayva to heplp me sleep tonight - the four main bearings that remained in the lower half of the crank case as I lifted it off all stayed in place. The one bearing that was stuck to the crankshaft does not sit as it should in the casing when I pressed it back in it seems looseish as it does not click into place like the other four. This bearing is the one that appears to be the worst for wear is there a reason for this is it connected to the proximity or not of the oil feeds?

I feel pretty confident that the casing has not been split before based on the 6 bolts being so tight, the white residue of what I assume is Hondabond & the brown staining of the engine casing. The drive chain is clearly worn consistent with being original plus the two guides appear to be made of solid black steeel like substance - it looks 42 years old.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: taysidedragon on March 21, 2021, 11:25:20 PM
Ted, I strongly suggest that you buy a Clymer or Haynes manual for your bike and read the section on measuring and selection of bearing shells.
It will save you having to ask so many questions on here. These engines and tolerances are nothing like old car engines.
The colour codes are selected for a brand new engine assembly with no wear on the journals.
If there is any wear on the journals now then the codes probably don't apply any more. The journals need to be measured very accurately,  as has already been mentioned.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 21, 2021, 11:43:32 PM
Ted, I strongly suggest that you buy a Clymer or Haynes manual for your bike and read the section on measuring and selection of bearing shells.
It will save you having to ask so many questions on here. These engines and tolerances are nothing like old car engines.
The colour codes are selected for a brand new engine assembly with no wear on the journals.
If there is any wear on the journals now then the codes probably don't apply any more. The journals need to be measured very accurately,  as has already been mentioned.

I have a Haynes Manual & a Cycleserve Servicing manual that came with the bike. I've found the Haynes one to be less than ideal as it covers the CB400 & CB 550 Uk & US versions & many of the sections seem unlike my bike. I will take a look at the section on journals as you suggest it might clarify what looks to me like a very over complicated situation. 

I ask questions as I am looking for the correct answers I do not understand so much about these engines. I appoligise if you find my thirst for knowledge in some way too basic, tiresome  or too numerate. I have a sound long standing knowledge of car engines spanning decades - I find a bearing shell marked as STD to  then be colour coded to more exactness an alien concept.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: taysidedragon on March 22, 2021, 12:34:55 AM
Ted, I  didn't mean to criticise you, just pointing you in the direction of the knowledge that is necessary to get these engines right.
The manual section on bearing codes clearly explains the colours/sizes available. It helps me to have prior knowledge on things like that before I get into the guts of the motor.
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 22, 2021, 03:37:49 AM
Ted, I  didn't mean to criticise you, just pointing you in the direction of the knowledge that is necessary to get these engines right.
The manual section on bearing codes clearly explains the colours/sizes available. It helps me to have prior knowledge on things like that before I get into the guts of the motor.

Hi Gareth, No offence taken I'm just being a bit contextually oversensative making me defensive.  I blame lock down making me a bit stir crazy, putting up barriers in my mind to the point where I wish I had never split the dam crankcase. I've felt completely out of my comfort zone for the last couple of days - that's not the normal me. I've read the section in the Haynes Manual as you suggested tbh it makes sense so I have a plan.  I'm going to measure up the main journals at 90 deg intervals and record the findings on a Excel chart. I have a couple of friends who are skilled in micrometer work that can help me out. That will enable me to make the right choice of main bearing replacements I need. The big end shells are all good thank goodness.
Cheers Ted
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: Trigger on March 22, 2021, 07:07:34 AM
As we used to say in the trade Ted, "you old boys worry too much ".
You just have to get your head around it. Forget everything you know from the past on English cars and bikes. It confuses my head the other way round as, i learnt Japanese engineering first so, when i look at a english built engine i wonder how the hell it ever worked  :o  The Honda engine relies on high oil pressure to float the crank and cam on a very thin film of oil.
   
Japanese engineering was a cut above the rest when they started all those years ago. It is a bit like racing engineering with the clearances and balance of the engine to enable a high revving engine. Down load a Honda Manuel and as you have the basic's so, it should come clear.   
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: AshimotoK0 on March 22, 2021, 09:23:49 AM
Eees a seemple  says Manuel  ;D ;D

[attach=1]

A old guy I know owned a Vincent Comet and Moggy 1000 Traveller from new in the mid 50's. He changed the oil in both machines religiously, probably sooner than required and he used both  as his regular transport until 2010. The Mog had done 300k and never had the engine rebuilt so he stripped it and took the crank to  Alex Carrs in Hull (Orcadian will know them  :) ) and they told him that the crank was still in tolerance.

I think it's all about oil changes and probably the luck of the draw with many old Brit engines.

Trigs right, download the manual from the Dropbox links and read several times and it all makes sense in the end. Getting Black & Blue  mains shells for the 400 is another matter as they are rocking horse poo.   
Title: Re: 400 four main bearings - will need replacement STD bearings.
Post by: McCabe-Thiele (Ted) on March 22, 2021, 12:22:56 PM
I agree about oil & filter changes I had a Manta GT/E that eventually started to get a timing chain rattle at 120,000 miles due to tensioner travel  issues. I had to take the cylinder head off to remove the front timing cover - almost everything I checked on the head, the bores etc was within manufacturers tollerances - I had owned it for most of it's life being a stickler for oil changes every 5k miles or 12 months. Never used cheap oil unless it was fully synthetic. Likewise I sold my Mk2 Carlton 2.0CDi at 190k miles - it never had a camshaft or chain replaced - my brother had it off me befor parting with it at a tad over 250k miles. Body work eventually rotted out.
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