Author Topic: Mains Jounal Measured with micrometer what colour code is needed ?  (Read 1751 times)

Online McCabe-Thiele (Ted)

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #15 on: April 10, 2021, 02:21:28 PM »
"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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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #16 on: April 10, 2021, 02:50:07 PM »
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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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #17 on: April 19, 2021, 10:10:28 PM »
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.



« Last Edit: April 19, 2021, 10:14:25 PM by Macabethiele (Ted) »
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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #18 on: April 19, 2021, 11:33:10 PM »
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.

Offline Bryanj

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #19 on: April 20, 2021, 01:05:44 AM »
 I would take the smallest pin size, work out code for that and run in for 500 miles

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #20 on: April 20, 2021, 09:00:49 AM »
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?
« Last Edit: April 24, 2021, 02:50:59 PM by Macabethiele (Ted) »
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #21 on: April 20, 2021, 09:03:57 AM »
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.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #22 on: April 20, 2021, 10:56:26 AM »
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.

Offline Bryanj

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #23 on: April 20, 2021, 02:49:04 PM »
When you measured it you said it could fit in two categories, use the smallest of those

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Re: Mains Jounal Measured with micrometer what colour code is needed ?
« Reply #24 on: April 20, 2021, 02:52:57 PM »
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..
« Last Edit: April 23, 2021, 05:49:03 AM by Macabethiele (Ted) »
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

 

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