It's time for crank bearings again ........

[Laverda Dave]

Hi All,
Its my first day here and I need some advice from the knowledgeable people who know and inhabit this forum.
Its a question about crankshaft bearings, big end bearings, bearing codes and general engine bearings.
Before joining the forum for 'real' today I have looked through a good number of posts regarding crank bearings but unable to find an answer I need.
I have bought a 400/4 in many, many boxes, you know, the 90% complete project with the vital missing 10% made of unobtainium materials.
I have completed stripping the half stripped engine and need advice about crank bearings.  Knowing from experience what a minefield measuring cranks is I used plastigauge to measure the clearances.  The stamping on the rear crankcase half are: BBBBA.  One of the crank webs has a number of 50106 although I am not sure if these actually mean anything.  I reassembled the crankcase with the crank installed and plastigauge placed on each bearing journal. I assembled the crankshaft in the bearings dry, no oil added to the bearing shells. I torque set the lower crankcase bolts to the required tension.  On disassembling I measured the plastigauge on the crank journals.  The readings were 0.050, 0.045, 0.063, 0.055, 0.050 (metric measurements).
Question 1: Can anyone please tell me if the bearings are within wear limits, I cannot find any reference in the Haynes or Clymer manuals advising what the wear limits of the shell bearings are?  I have a nasty feeling they are terminally worn. This leads to:
Question 2: How do I measure the crank journals accurately? I have a mic but this only reads down to 100th of a mm, Honda measurements are in microns (32+0 -0.010u)! Having measured the crank journals using the mic I have obtained the following readings: 31.76, 31.70, 31.82, 31.80, 32.00. Unfortunately I cannot believe any of the readings I have obtained as I get a slightly different reading every time I measure each journal, I'm talking of differences of 100ths of a mm but its enough to cast serious doubt.
If I do need new bearings I think I need Black, Black, Black, Black, Yellow?
Question 3: If I need black bearing shells does anyone know of a supplier, DS and CMSL don't have any. Should I start crying yet?
Question 4: Big ends -  Any advice please on a type of socket to use to remove the big end nuts, the nut is obscured by the curvature of the big end, a 3/4 socket is too big and a 1/4 socket wont move the nut. It doesn't hep that someone has already been there previously and rounded a couple of the bearing nuts, not badly but Mr Honda obviously didn't put them in like that!
Question 5: The con rods are marked with what appears to be a number and a letter, I though they should only have a number.  The numbers (and letters) I have found on each con rod are: 1D, 2D, 21(should it be an 'I'), 21 (same as rod no.3). The rods and ends are correct pairs, I can see they haven't been swapped with each other as the numbers and letters are stamped half on the main rod and half on the lower shell cap.  Can anyone advise what bearing shell colours I need?
Question 6: Can the con rod bolts be reused once undone or are they stretch bolts? (exxxpppeeennnsssiiiveee  )
Question 7: Does anyone know the OD and ID of the main engine bearings, the parts manual only provides part numbers, can anyone recommend a bearing supplier? Do I, or should I, replace the main engine bearings considering I have the engine in bits and never heard it running?

Apologies for all the questions, its just the crankshaft bearing issues appears to be a can of worms!

One last question, can anyone recommend a good painter, I have a tank with a slight dent in primer and a couple of new sidepanels from DS that also require painting in the F2 maroon with the pinstripes.

Thanks for reading this far  .

Dave

[AshimotoK0]

The Haynes manual give crank journal clearance up to 0.048mm clearance upper limit standard and 0.08mm maximum . So your measurements are  all on the upper side/ slightly above standard book value   but all below the wear limit. Some pics of the shell and journal surfaces would help they should not be scored or badly scuffed. They should have a matt appearance no shiny points. The numbers 1,2,3 on the con rod denote the con rod big-end hole size or 'allowance'. The other  letter marking is the weight code. Have you downloaded the manual from my Dropbox link?  I personally re-use big end bolts but it's scorned on by some people. I reckon it's fine for the kind of use a classic gets but probably not for racing. The codes marked on the crank are only any use for when the crank was new as they obviously don't take account for any wear experienced during the mileage done so far. You may need to take the crank to someone who has the correct measuring equipment. Then we can work out the correct shells, should you decide to replace them. Not entirely sure but I believe black shells are very hard to find. As I said, close-up pics of the journals will be a good start.

Bryan, Trigger & Oddjob on here are your engine experts ..as they did it (do) it for a living but I thought I would start the ball rolling for you with my amateur comments. You can measure the journals with a very accurate micrometer  and a proficient man on the job but Honda used air gauging in production. I ground down a good quality socket to fit the big end nuts. Some deep sockets have thinner walls. You need a decent make though.

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For Painting: Menno Dek in Germany /Andrew Parnably North Yorks would be my recommendations. Andrew did my 750K0... Menno is going to do my 500/4 K0. Spraying candy paint is a specialist area and a work of art in my book if done properly BUT you pay  quite a bit for top quality.

[Laverda Dave]

Thanks for all the great advice so far, much appreciated.  I will take some photos of the offending articles and post this evening.
Dave

[Chris400F]

Menno for paint is a member on this forum, his web site is here if you want to take a peek:
http://www.tankspraypainting.eu/

[Laverda Dave]

Hi All,
Thanks for the advice so far.
I have taken some photographs of the journals and the bearing shell.
All the journals are smooth with no ridges, nicks or scores.  The centre of each journal in the location of the oilways are all smooth with no wear ridges. The photos are very close up so every tiny mark shows and what appear to be nicks etc is actually dust! Any red marks or grease marks is plastigauge residue.
I have taken a photo of the 'worst' bearing shell, they are all actually like this. They are all matt , not shiny (in this instance the camera has lied and the shine is actually the reflection from the camera flash!) The photo is super enlarged, every mark shows!
8 of the bearing shells are marked as BD4K-A, these shells locate in the 'B' housings of the crankcase.  The remaining 2 shells are marked as BD4J-A and these locate in the 'A' housings of the crankcase (markings are BBBBA).
So, what is the verdict, can I reinstall these shells, as AshimotoKO advises, they are within wear limits however, if you think they need replacing I shall subject to being able to get the colours I need 

Any advice greatfully received.

Does anyone know where I can get the remaining engine bearings such as the roller bearings and enclosed needle rollers on the gear shafts?

Thanks again all.

Dave

[Bryanj]

Nothing wrong with those shells if you can get them back in the place they came out of

[AshimotoK0]

Nothing wrong with those shells if you can get them back in the place they came out of

Bryan's your expert and I agree. The shell markings mean nothing, they are production codes,  only the paint dab on the side, which even when new is pretty hard to distinguish and fades or discolours after years in the heat and oil is your clue to their size.

This is your best place for the bearings but  are you sure the originals need replacing. looking at your crank then they could well be OK to re-use.

http://www.yamiya750.com/index.php?main_page=product_info&cPath=179_273_206_210&products_id=3069

Dave at Saisei can order these for you but obviously there is VAT and import duty. The codes in the pic should tell you where to get alternative individual bearings but some are specially grooved  with 'Nick' as Yamiya describe them. some of those bearings are incredibly cheap from Yamiya but I guess it's the needle rollers that bump the kit price up. The 6003 bearing is the same as on the CB750 (clutch release) and comes in a Honda bag and mega cheap from them

cheers ... Ash

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[Laverda Dave]

All excellent news   
Thank you for all your time and knowledge,  I can set the spanners in motion 
Dave

[Laverda Dave]

Hi Oddjob.

I took your advice and gave the crank a good clean yesterday.  Whilst it was wet with gunk in the parts washer I noticed the edge of two of the crank webs had the letter 'A' stamped on them.  The style of lettering matched those on the conrods. I couldn't find any other number or letter other then the numbers shown on my original post (added here again).  Once the crank was dry the letters on the edges of the webs disappeared! I'm going to paint the whole bike in this stuff and avoid paying road tax (as long as it doesn't get wet and be seen!)
Thanks for you help and advice though, appreciated 
Dave

[stevush]

I'm having a bit of a problem marrying up crank numbers and letters so I've resurrected the thread.

On the outer casing I have CBBCB.

All from alternator side I have:-
On the crank webs (all very clear) A2 A1 B1 B1 1
On the conrods (all very clear)I have C C C C, but the numbers are almost illegible(it looks like a 2 or a 3) 3 2 2.
So what main and conrod bearings am I looking for, can anyone tell me please ?

Thanks
Steve

[stevush]

Wow, thanks for the quick reply ODDJOB, much appreciated. I'm assuming DS would be the only UK supplier of these ?

Thanks
Steve