1981 Honda CB650 Custom Main Crank Bearings

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Whacky Wheels
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Joined: Sat Nov 25, 2017 4:07 pm

1981 Honda CB650 Custom Main Crank Bearings

Postby Whacky Wheels » Tue Dec 31, 2019 6:36 am

Hi Guys!

I know this is a topic that is exhausted on forums. But I am on the hunt for a full set of 10x main crank bearing C shells, color code Green, for my 1981 Honda CB650 Custom. Mine do not measure bad at all, but they have some physical damage to them from sitting on a shelf for the past year :cry: (it almost looks like some bubbling of the top layer of the bearing. Bike only has 53 000km on, but by the looks of the engine, has not had it's annual oil change at all.

I have bought a new set of green con rod bearing shells, and while I am busy, I want some peace of mind to know that my crankshaft will last forever, as I'm quite on top of oil changes and maintenance.

I've read a few threads and some of them says that the CB550 bearing shells will fit the CB650 as well. Does anyone know if there is any truth to that statement? David Silver has the Green CB550 mains in stock (13317-323-000), but NOBODY has for the CB650 (13317-426-003), as they are no longer produced. If the 550 bearing dimensions don't work, will the 750's work?

Any and all help is appreciated!!

Best wishes for the new year!
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Ox Moto
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Joined: Mon Dec 04, 2017 8:29 am

Re: 1981 Honda CB650 Custom Main Crank Bearings

Postby Ox Moto » Tue Dec 31, 2019 10:15 am

Cmsnl might be your best bet

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Volker_P
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Location: southern Germany

Re: 1981 Honda CB650 Custom Main Crank Bearings

Postby Volker_P » Thu Jan 02, 2020 2:57 am

Cannot say much to your shells from that picture. In case this should be oxidation: Oxidized stuff is typically harder than bulk material and a bumpy hard layer at reduced oil gap does not sound like something someone wants for bearings.
I probably would try to treat a "bubble" with a scalpel to get an idea what it is and if they can be reasonably removed.

Good news is that rod and main shells for CB500, CB550 and CB650 should be the same.
Had that discussion elsewhere some time ago and our measured dimensions seemed to be the same.
Did not prove it however by doing it myself yet.
If you get and mount nominal 500/550 shells in a 650 case please report the result here.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

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Whacky Wheels
Posts: 7
Joined: Sat Nov 25, 2017 4:07 pm

Re: 1981 Honda CB650 Custom Main Crank Bearings

Postby Whacky Wheels » Sat Nov 04, 2023 1:03 pm

Oh man, what a journey on my CB650 so far! I can confirm that the shells in the 500 and 550 are the same as the 650. They work and fit perfectly in the 650 crank case with the exact tolerances specified (Haynes Manual). Enjoy all!

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Volker_P
Posts: 5508
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: 1981 Honda CB650 Custom Main Crank Bearings

Postby Volker_P » Tue Nov 07, 2023 4:23 am

Thanks for the confirmation of CB 500/550/650 four bearing shell compatibility.
Hope you got everything together and running.
Sounds like things were not that straightforward.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum


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