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SOHC.co.uk Forums => CB350/400 => Topic started by: Rogerxlixi on January 31, 2023, 01:44:09 PM

Title: Yellow (Size D) Main Bearings
Post by: Rogerxlixi on January 31, 2023, 01:44:09 PM

Hi All,

Just in process of an engine rebuilt and have worked out what main bearings i need. Namely 6 yellows and 4 greens. The greens look to be in good supply, but can't say the same for the yellows. David silvers and CMSNL both out of stock, found another site over in japan but still nothing.

Does anyone have any leads on yellow bearings at all?
Any other solutions out there at all?

Toying with the idea of trying a green out and seeing how the clearance is with plastigauge.

Title: Re: Yellow (Size D) Main Bearings
Post by: Trigger on January 31, 2023, 02:03:57 PM

Unless the crank is new, the journals will be worn and you should be able to upsize to green  ;)

Title: Re: Yellow (Size D) Main Bearings
Post by: Rogerxlixi on February 01, 2023, 11:15:07 AM

Thanks for that trigger, appreciate it.

Having finally found a battery for my Vernier the crank journals do measure up slightly worn and a smidge below the 32mm nominal. Will be getting greens all round. 

Title: Re: Yellow (Size D) Main Bearings
Post by: Trigger on February 01, 2023, 12:45:49 PM

You can not measure with a Vernier, you need a micrometer that can measure correctly and precise  ;)

Title: Re: Yellow (Size D) Main Bearings
Post by: McCabe-Thiele (Ted) on February 01, 2023, 02:41:27 PM

And a decent micrometer as well.

Title: Re: Yellow (Size D) Main Bearings
Post by: Oddjob on February 01, 2023, 05:03:34 PM

Just go up a size and fit greens if the crank looks ok.

Title: Re: Yellow (Size D) Main Bearings
Post by: 400 Cafe Racer on February 03, 2023, 05:16:12 PM

Quote from: Trigger on January 31, 2023, 02:03:57 PM

Unless the crank is new, the journals will be worn and you should be able to upsize to green  ;)

Rogerxlixi
As well as physical instrument measuring, you should be able to get a final accurate clearance reading confirmed by assembling the bearing with "Plastiguage", then  torqing to correct setting, then disassemble to read the actual clearance for each journal. Its a bit time consuming but gives a clear result IMHO.

Dennis :)

Title: Re: Yellow (Size D) Main Bearings
Post by: McCabe-Thiele (Ted) on February 03, 2023, 08:55:47 PM

I agree with Dennis it's fiddly but Plastigauge works - I practiced on the con rods as it's simpler - then did the mains.

I will do the same on my 500.