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Thread size alternator cover, points cover?

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GregMcN
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Location: Richmond, North Yorkshire, UK

Thread size alternator cover, points cover?

Post by GregMcN » Mon Sep 02, 2019 3:50 pm

Can anyone confirm the threads on the alternator cover and the points cover of a cb77.
They are both m5 but standard 0.8mm pitch screws do not seem to fit.
It looks like could be 1.0mm pitch but this is a pretty rare size so wanted to check whether this is the case rather than perhaps someone having forced something in and damaged them.

Thanks Greg

DJM
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Location: Chesterfield UK

Threads sizes.

Post by DJM » Mon Sep 02, 2019 5:34 pm

Greg,

these are the 'old' JIS Spec threads 5mm x 0.9mm, went out of use after the CB72/77 series bikes. I think some late model (CB/CL series) bikes may have the 'new' fasteners from the factory so you need to be careful.

You can still find the JIS spec fastners on the internet sometimes but it might be easier to helicoil them with a standard 5mm x 0.8mm insert and then use standard off the shelf screws

GregMcN
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Joined: Tue Jul 04, 2017 3:34 pm
Location: Richmond, North Yorkshire, UK

Post by GregMcN » Tue Sep 03, 2019 4:26 am

Thanks Dennis, I did not realise that JIS was a different thread I just thought that the screw head was different.

Greg

mcconnellfrance
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Location: Ayr, Scotland

Post by mcconnellfrance » Wed Sep 04, 2019 2:15 am

David Silver Spares or CMSL used to have the correct JIS screws for these locations.

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Tim Allman
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Location: Guelph, Ontario, Canada

Post by Tim Allman » Wed Sep 04, 2019 10:34 am

I bought some screws from DSS a while back expecting that I would get screws with the old JIS thread pitch, especially given that they list the screws by application.

https://www.davidsilverspares.com/CB77-305/part_43594/

I was disappointed when they arrived because they were, of course, ISO threaded. When I contacted them about this they told me that Honda had superseded the part. I suggested that they might mention the discrepancy in their catalogue but nothing has happened. No doubt there are many others who have bought 5 mm screws that are not as described and are therefore useless.

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