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Big End Bearing Replacement

Posted: Wed Oct 07, 2015 10:22 am
by LukeVan
To start off, there are tons of people who say "ahh just buy a new engine and save yourself the hassle and blah blah blah"

I cant do that. I can only get by with the answers to the questions I have now.

I blew one of my big ends taking a long corner while low on oil, and rode the bike home after that.

Ive stripped my engine down, and have removed the big end (I will be replacing all 4), but when i contacted honda they told me that i needed the color of the bearing ( :o :o :o ) can anyone help me with this? I dont know how to find out what color code they are.

TIA,
Luke

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 10:52 am
by Variablevalves suck
Hi Luke,

You need the workshop manual, this will have different journal bearing listed with different colour codes.
You use a product called plastigauge to get a oil clearance that then relates to a bearing colour and order said bearing.

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 11:56 am
by TyeNoodle
You may well be able to see the colour dot on the side of the bearing shell too.

Good luck!

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 12:28 pm
by Neosophist
LukeVan wrote:To start off, there are tons of people who say "ahh just buy a new engine and save yourself the hassle and blah blah blah"

I cant do that. I can only get by with the answers to the questions I have now.

I blew one of my big ends taking a long corner while low on oil, and rode the bike home after that.

Ive stripped my engine down, and have removed the big end (I will be replacing all 4), but when i contacted honda they told me that i needed the color of the bearing ( :o :o :o ) can anyone help me with this? I dont know how to find out what color code they are.

TIA,
Luke

If it was low enough on oil to ruin a big end and you rode it home have you checked everything else for damage?

Bearings and the top end don't fare well without oil.

As for the bearing shells you need to download the service manual from the downloads section.

Use the figures and plastigauge to check the engine is in tolerance. Rebuilding a worn out motor is a waste of money.

It also details how you can accurately measure the clearances on the big-end bearing shells and will provide you with what sizes to use given your readings.

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 3:42 pm
by vfrman
You are going to need to get into the motor to find out the size (color code) of the bearing. The crank and case have codes assigned to them that you cross reference to the manual to show which bearing should be installed.

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 8:31 pm
by LukeVan
Neosophist wrote:
LukeVan wrote:To start off, there are tons of people who say "ahh just buy a new engine and save yourself the hassle and blah blah blah"

I cant do that. I can only get by with the answers to the questions I have now.

I blew one of my big ends taking a long corner while low on oil, and rode the bike home after that.

Ive stripped my engine down, and have removed the big end (I will be replacing all 4), but when i contacted honda they told me that i needed the color of the bearing ( :o :o :o ) can anyone help me with this? I dont know how to find out what color code they are.

TIA,
Luke

If it was low enough on oil to ruin a big end and you rode it home have you checked everything else for damage?

Bearings and the top end don't fare well without oil.

As for the bearing shells you need to download the service manual from the downloads section.

Use the figures to check the engine is in tolerance. Rebuilding a worn out motor is a waste of money.

It also details how you can accurately measure the clearances on the big-end bearing shells and will provide you with what sizes to use given your readings.
The oil was only low enough to expose one of the big ends when I took a long sweeping turn. (+/- 10 seconds) everything is well intact. I stripped engine down and all is good. Found the color code, I didn't expect it to be black so I was very confused as it just looked like oil.

Thanks for the help guys (y)

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 9:17 pm
by vfrman
Umm....black isn't one of the colors. It's either Yellow, Green, or Brown, depending on the codes found on your cases and crank.

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 10:15 pm
by Variablevalves suck
Importantly did the bearing simply pick up against the crank due to low lubrication or did it lock and then spin in the casing.
If it's spun then you need to decide if the engine casing is ok to refit a new journal to.

You need to check everything over as I'm sure the mains are oil fed and not simply sat in a bath so I would say oil was not picked up from the sump and would have not been pumped to other parts of the engine, might be wrong but most engines are pressure feed.

Re: Big End Bearing Replacement

Posted: Wed Oct 07, 2015 11:34 pm
by hunter
I have only ever seen one engine with all the main bearing the same colour code,
The code lettering is stamped on the casing behind the clutch,
It will be something like ABBB or BABB or another combination.
And as vfrman said no black. just Green Brown or Yellow.

Re: Big End Bearing Replacement

Posted: Fri Oct 09, 2015 11:29 am
by LukeVan
[img]http://images.tapatalk-cdn.com/15/10/09 ... 0c994f.jpg[/img]

This is the current state of the engine. Do I need to remove the clutch unit to see this.

Sorry for my ignorance. This is my first big end rebuild.