Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: McCabe-Thiele (Ted) on April 09, 2021, 11:46:53 AM
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Today my BiL measured up my mains journal as follows with a decent micrometer the mains were measured in several places and were nice & round.
Crank Casing Code is CAABA where C is number 1 journal.
In order they were No:1 32.03, No:2 32.03, No:3 32.01, No:4 32.03, No:5 32.03
If the Crank Case Code is applied to the tables we think I need No:1 Blue, No:2 Brown, No:3 Green, No:4 Black, No:5 Brown
Does this look right to the folks here that know if Black is not available we think Brown as the next best alternative?
Or I'm not reading the tables correctly ??
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Ted,
better measure those crank journals again. it should be under the 32 mm size down to 31.97.
What manual are you using? in the Honda manual no reference is given to the codes on the case, i normally measure the bore of the case. But the Haynes manual does refer to the case codes. i have used them in the past and have not had any problems. ( i still double check with the bore measurements)
Kevin
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Ted,
better measure those crank journals again. it should be under the 32 mm size down to 31.97.
What manual are you using? in the Honda manual no reference is given to the codes on the case, i normally measure the bore of the case. But the Haynes manual does refer to the case codes. i have used them in the past and have not had any problems. ( i still double check with the bore measurements)
Kevin
I was using the Honda Parts Manual but it seems my Cycleserve Manual gives additional colours !!
I'm going to get the journals checked again myself with a different Micrometer as well.
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Something wrong with your measuring, need another 0 and plastigauge is more reliable. Never seen 4 different shells on a crank ever ;)
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Something wrong with your measuring, need another 0 and plastigauge is more reliable. Never seen 4 different shells on a crank ever ;)
The existing shells are 3 Green & 2 unknown as there is no visible colour markingsf for me it's a conundrum.
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You could mic the green shells with a small bar inside the arc in same direction as crank goes, then do the same for the "mystery" shells to get some view of a match or not.
Put a metal bar (thinking silver steel as it's ground to diameter, or similar) in a vice, lay the shell over it and mic the two together to get accurate reading.
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Ted,
Can you see the crankshaft markings? A and 1 in this example.
[attach=1]
Ignore the red circles.
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Ted,
Can you see the crankshaft markings? A and 1 in this example.
(Attachment Link)
Ignore the red circles.
No visible markings on the crank aside from the balance drillings holes on the crank webs.
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You could mic the green shells with a small bar inside the arc in same direction as crank goes, then do the same for the "mystery" shells to get some view of a match or not.
Put a metal bar (thinking silver steel as it's ground to diameter, or similar) in a vice, lay the shell over it and mic the two together to get accurate reading.
I'll look at that I would be happy putting 3 sets of green shells in 2,3 & 4 but 1 & 5 although the same are at present unidentified
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I had the same issue with one of my crankshafts, only a couple of markings visible. I took my crankshaft to an engineering company I knew and had the crankshaft measured. As Trigger stated all the measurements were identical.
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I had the same issue with one of my crankshafts, only a couple of markings visible. I took my crankshaft to an engineering company I knew and had the crankshaft measured. As Trigger stated all the measurements were identical.
At the risk of annoying everybody I feel as though I'm stuck with what to me seems a bizzare batch numbering system of crank bearings with no cross refferencing.
I have 2,3 & 4 mains shells marked as STD D61-A as a batch number - there is a trace colour marking on just one of these as being Green.
The other two 1 & 5 are marked as STD D6H-A at present unidentified as regards to colour as its long since gone.
Has anyone here come across batch number D6H-A with an identified associated colour ?
Am I right in thinking that the lower crank casing marks CAABA refer to the O/D of the shells when they were originally sized by Honda ?
At present my next move is to try to get the crank mains re-measured with a different micrometer - just maybe I can somehow measure the old bearings for 1 &5 thickness wise at a local engineers when I take the upper crank case for the cam chain adjustment bolt modification.
Except that it does not allow for wear Green might be ok for the centre three main bearings.
Not sure how to use Plastiguage to help with identifying 1 & 5.
I'm completely stuck at the moment but time & help here will I'm sure help me see the wood from the trees eventualy !!!!!
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"Am I right in thinking that the lower crank casing marks CAABA refer to the O/D of the shells when they were originally sized by Honda ?"
It's the measured bore size of the crankcase when inspected after line boring operation.
A being smallest, C the largest (this from a 750 manual) sizing different but protocols the same as far as I know.
Have you got the charts from Honda manual that explains it and gives you the correct colour to use? If so, you can with accurate crankshaft mic measurements derive the colours from those letters and just the accurate dimension.
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(https://live.staticflickr.com/65535/51106363387_3e19a12f13_z.jpg) (https://flic.kr/p/2kS6tjk)Screenshot 2021-04-10 132841 (https://flic.kr/p/2kS6tjk) by Macabe Thiele (https://www.flickr.com/photos/187487200@N03/), on Flickr
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"Not sure how to use Plastiguage to help with identifying 1 & 5."
Likely that these two are going to be at least Brown to then check with plastigauge.
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"Not sure how to use Plastiguage to help with identifying 1 & 5."
Likely that these two are going to be at least Brown to then check with plastigauge.
That's an interesting comment as I have completely unscientifically asigned Brown to 1 & 5 on the basis that my cranshaft main jounals are most likely to be in the range 1 of the table so using the crankcase allowance in column C that gives me Brown, as both bearings 1 & 5 are the same batch number STD D6H-A they are both Brown plus the only hint of any colour on the shell edges is rust brown!
Next question to self is what size plastigauge do I need for the clearance range of 20-46.
I am guessing I only really need to use the 8 bolts that secure the mains when checking not put back all the upper & lower crancase bolts.
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I was looking at it from the probability of Honda making the cases with wider tolerances on both those journals AND the crankshaft, and so making requirements for the most extreme shells.
The cases you could "possibly" see if line boring that one end could have characteristic marginal tolerance matching (depending on production method) but crank pins done individually wouldn't conform to that potential error as ground individually.
So a machine shop guess of having crank likely to be very close to the target in those two 1&5 locations paired with the case tolerances you have, to give reasonable scenario.
Plastigauge should be on target if that's how they turn out, but accurate mic-up of those two journal will absolutely confirm.
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I have bought myself a reasonably decent micrometer - I checked it against the 25 mm standard with the crank & micrometer at room temperature and have taken readings on all 5 journals.
All five main journals are measuring as 31.99 mm the Crank Case Code is C-A-A-B-A what are the corresponding colour codes here please as I can't follow the table with any confidence?
As 32 +0 -0.010 & 32 -0.01 to -0.020 appears in two columns in the tables my measurement seems a bit pig in the middle I'm thinking journal 1 that has case code C is Brown or Black.
Journals 2,3,&5 are Yellow or Green. Journal 4 is Green or Brown.
The only journal that was still showing a colour code was No 4 that was definitely Green. If the codes on the shells mean anything at all then !1 & 5 are the same leaving 2, 3 & 4 as the same.
Advice / comments sought please. I can't see any markings on the crankshaft itself just holes where the webbs have been drilled for balancing presumably.
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Have you got a vernier scale on the mic to give the 3rd decimal place number?
It'll show which way the tolerance is leaning to and help make the decision easier.
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I would take the smallest pin size, work out code for that and run in for 500 miles
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I would take the smallest pin size, work out code for that and run in for 500 miles
Hi Bryan,
Sorry for my ignorance - not sure what you mean by the smallest pin size?
Am I right in thinking that as you move down the table the shells are in effect thicker to alow for crank wear or smaller diameters of journal?
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Have you got a vernier scale on the mic to give the 3rd decimal place number?
It'll show which way the tolerance is leaning to and help make the decision easier.
Sorry it does not have anything beyond the second decimal place its a Moore & Wright new item.
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Have you got a vernier scale on the mic to give the 3rd decimal place number?
It'll show which way the tolerance is leaning to and help make the decision easier.
Sorry it does not have anything beyond the second decimal place its a Moore & Wright new item.
You can still get indication of if under or over the 0.01 increment.
When you mic the journal, if you have any "traction" as you undo the mic, then you've probably sprung the gate a very tiny amount. By just touching the contact at very very light sliding pressure, then look at the marking to see if you are above or below the 0.01 mark, even by a small amount.
It can tell you if they are between 0.00 and 0.01 or between 0.01 and 0.02 which will give you the correct position on the colour table.
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When you measured it you said it could fit in two categories, use the smallest of those
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Have you got a vernier scale on the mic to give the 3rd decimal place number?
It'll show which way the tolerance is leaning to and help make the decision easier.
[/quote
You can still get indication of if under or over the 0.01 increment.
When you mic the journal, if you have any "traction" as you undo the mic, then you've probably sprung the gate a very tiny amount. By just touching the contact at very very light sliding pressure, then look at the marking to see if you are above or below the 0.01 mark, even by a small amount.
It can tell you if they are between 0.00 and 0.01 or between 0.01 and 0.02 which will give you the correct position on the colour table.
I have done that now - that thanks. Ted
Settled now on Black, Brown & 3 Green sets of shells - I will plastiguage for peace of mind when I start to rebuild the casing..