Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: Yurkie on August 12, 2016, 02:38:44 PM

Title: 64mm Piston rings
Post by: Yurkie on August 12, 2016, 02:38:44 PM

Hi,

I'm very slowly rebuilding my 1977 F2. I had a phone call from the machine shop advising that the new piston rings are to small and I need 64mm.

So if I have researched correctly the bike has had a 812 big bore kit fitted at some point. Does anyone know where I can buy 64mm piston rings from? I did read that the cb350 piston rings would work, is the any truth in this?

Thanks for your help

Title: Re: 64mm Piston rings
Post by: Trigger on August 12, 2016, 11:18:44 PM

A 64mm piston is a Henry Abe big bore kit that the rings are no longer available. Yes, you can use 350 rings but, it is a lot of work. Try looking for another STD set of barrels.

Title: Re: 64mm Piston rings
Post by: flatfour on August 13, 2016, 09:59:11 AM

I have a set of barrels taken from my K2 when the top - end was overhauled, not sure whether they are the same?

Title: Re: 64mm Piston rings
Post by: Chris400F on August 13, 2016, 10:57:11 AM

Could you go for a larger big bore kit like this one with 65mm bore, says it is suitable for F models.
http://www.ebay.co.uk/itm/HONDA-CB750-F-SOHC-75-78-836cc-BIG-BORE-KIT-65mm-PISTON-RINGS-GASKET-/131255080464?hash=item1e8f699610:g:ff8AAOSwnDZT1vo0

Title: Re: 64mm Piston rings
Post by: hairygit on August 13, 2016, 11:56:37 AM

Or try this set, tried and tested by several members on here, e bay item. 252487306630

Title: Re: 64mm Piston rings
Post by: Chris400F on August 13, 2016, 12:02:51 PM

I saw that one but it is listed for K models, is it suitable for the F engines?

Title: Re: 64mm Piston rings
Post by: Yurkie on August 15, 2016, 07:40:56 PM

Thanks for the advice everyone. Think I'll go with the bigger bore option. Has anyone got experience of using the 252487306630 with a F2 supersport, and would I need to modify/upgrade anything else?


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