Author Topic: Crank Journal Bearing condition...  (Read 738 times)

Offline Oz350Four

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Crank Journal Bearing condition...
« on: April 17, 2021, 09:04:53 AM »
I bought a basket case 75 CB400 four and am in the process of stripping it down for a rebuild.
I'm not one for doing things half arsed like the previous owner did but I don't want to have to spend any more money than necessary.
Anyway, I'm down to the point where Ive split the cases and would like folks opinion as to the crank journal bearings.
Can these bearing halves be reused or should I replace them.
So as to not drown the would be reader in pictures I've posted the lower ones so as to get feedback.
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Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: Crank Journal Bearing condition...
« Reply #1 on: April 17, 2021, 09:22:11 AM »
Hi and welcome to the Forum.
They have pitting and scoring, I would change them if it were my engine. Also check the crank for damage / wear.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline McCabe-Thiele (Ted)

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Re: Crank Journal Bearing condition...
« Reply #2 on: April 17, 2021, 10:03:51 AM »
I agree with Julie, they are similar to how mine are - when you are that far into the engine get them replaced.
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

Offline royhall

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Re: Crank Journal Bearing condition...
« Reply #3 on: April 17, 2021, 11:45:12 AM »
I would also say new shells required there.
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline Bryanj

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Re: Crank Journal Bearing condition...
« Reply #4 on: April 17, 2021, 11:54:19 AM »
Dirty oil not changed often enough, yes change them and infortunately with that marking check the ends as well

Offline philward

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Re: Crank Journal Bearing condition...
« Reply #5 on: April 17, 2021, 09:43:39 PM »
Welcome to the forum - I agree with the previous posts and would change those shells.
Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
Kawasaki ZZR1100D3 (1995)
Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline Oz350Four

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Re: Crank Journal Bearing condition...
« Reply #6 on: April 18, 2021, 12:01:52 AM »
Thanks folks for the feedback / advice...
Now to work out what colour / number I need and try and source them.
Stay tuned, I will no doubt have further questions.
And, just to keep a few of you busy I've posted a picture of handiwork by the previous owner so you might get an idea what I'm up against.
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Online K2-K6

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Re: Crank Journal Bearing condition...
« Reply #7 on: April 18, 2021, 08:19:25 AM »
Doesn't look too bad inside, agree with old oil used in condition of shells. 

If you're not familiar with 400 four, that lower enging mount (rhs in photo) and right next to the main oil feed to filter housing, is the one that gets punctured when people use too long a frame mount bolt.

Usual mode of operation  :) is when removing a crash bar that's used a longer bolt,  that when put back in without bar, goes straight into the oil feed to crack it. Make sure you've got the right one to avoid grief.

Currently live and may help with shells http://www.sohc.co.uk/index.php/topic,25221.0.html

Welcome to the forum too.

Also a very good appreciation of 400 four rebuild and worth a read through http://www.sohc.co.uk/index.php/topic,14049.0.html if you've not already seen it.

Offline Oz350Four

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Re: Crank Journal Bearing condition...
« Reply #8 on: April 18, 2021, 08:54:08 AM »
Thanks K2-K6,
I had known about the old long bolt in the mount issue... but did you notice the oddity in the crank case bolts...???
I have started reading Nurse Julie's build thread... quite detailed I must say. I wish I had half the tools / facilities / knowledge at my disposal..!!  :D :)

Online K2-K6

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Re: Crank Journal Bearing condition...
« Reply #9 on: April 18, 2021, 09:09:02 AM »
Can see the extra dome bolt, has the previous owner put a stud in there?

Offline Oz350Four

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Re: Crank Journal Bearing condition...
« Reply #10 on: April 18, 2021, 09:24:32 AM »
Yep, obviously lost / broke one the bolts so used a spare stud - it didn't have much torque on it whereas the others all felt like he'd used a four foot pipe on the wrench doing them up.... quite the bush mechanic..!!

Offline royhall

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Re: Crank Journal Bearing condition...
« Reply #11 on: April 18, 2021, 09:27:34 AM »
Thanks folks for the feedback / advice...
Now to work out what colour / number I need and try and source them.
Stay tuned, I will no doubt have further questions.
And, just to keep a few of you busy I've posted a picture of handiwork by the previous owner so you might get an idea what I'm up against.
(Attachment Link)
As always these old bike repairs are 25% mechanical wear and 75% previous owner abuse. Seems to be even worse on the American import bikes for some reason (Big Bubba).
Welcome to the forum by the way.
« Last Edit: April 18, 2021, 09:34:24 AM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

 

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