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Author Topic: Stuck - assistance needed (pistons??)  (Read 1160 times)

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Offline jasonseasen

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Stuck - assistance needed (pistons??)
« on: September 02, 2009, 08:09:47 PM »
Hi,
My cylinders measure at 64.4mm at the top/64.2 at the bottom. I have read that CB350 pistons would work, any other thoughts or comments to help me? I was initially going to bore to 65mm, but discovered my rings did not fit the pistons I had. I am unsure of what direction to go??
Thanks,
Jason
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Stuck - assistance needed (pistons??)
« Reply #1 on: September 02, 2009, 08:30:43 PM »
CB350 pistons are the same diameter as the 810 kits. 64mm. The domes are too high without some seroius machining that probably no one is equipped to do or has the knowledge to do without some serious charges.

You gave us measurements of your cylinders but no mention of any ID of your pistons. We need pictures, measurements &/or complete description of any info that may ID these pistons. Rings can be had or the pistons can be worked on to fit existing rings.

What rings do you now have?   
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Offline bucky katt

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Re: Stuck - assistance needed (pistons??)
« Reply #2 on: September 02, 2009, 10:05:17 PM »
Quote from: Jerry Rxman Griffin on September 02, 2009, 08:30:43 PM
CB350 pistons are the same diameter as the 810 kits. 64mm. The domes are too high without some seroius machining that probably no one is equipped to do or has the knowledge to do without some serious charges.

You gave us measurements of your cylinders but no mention of any ID of your pistons. We need pictures, measurements &/or complete description of any info that may ID these pistons. Rings can be had or the pistons can be worked on to fit existing rings.

What rings do you now have?   

how high DOES it make the compression and any idea as to how much to remove? i do have access to a full machine shop.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Stuck - assistance needed (pistons??)
« Reply #3 on: September 02, 2009, 10:21:44 PM »
Fuzz,

I believe in the 12.5 to 1 range but I could be wrong. Big Jay could probably jump in on this one. I believe that's what he started with perhaps?
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline bucky katt

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Re: Stuck - assistance needed (pistons??)
« Reply #4 on: September 03, 2009, 03:35:54 AM »
yikes! too high for a street bike then. i've been wanting a set of 810/811/812 pistons but not that kind of compression.   sorry, thread hijack over  ;D
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Of all God's creatures there is only one that cannot be made the slave of the lash. That one is the cat. If man could be crossed with the cat it would improve man, but it would deteriorate the cat.
Mark Twain - Notebook, 1894

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Stuck - assistance needed (pistons??)
« Reply #5 on: September 03, 2009, 11:32:08 AM »
Jason,

Where are you?

Fuzzy,

I have a set of 3 NOS 64mm pistons. Unmarked so I can't ID them. If we could find a 4th we would have a set for you.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline jasonseasen

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Re: Stuck - assistance needed (pistons??)
« Reply #6 on: September 03, 2009, 12:02:04 PM »
Hi,
I live in Alberta, Canada.
I have a set of original 61mm pistons, a set of 65mm ART pistons, and a set of 65mm Wiesco rings that do not fit the 65mm pistons. So with all this, nothing fits anything. I am going to have to get rid of a few things and buy others.
Jason
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Offline kenolds

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Re: Stuck - assistance needed (pistons??)
« Reply #7 on: September 03, 2009, 12:39:16 PM »
Well, sounds like you have to bore no matter what (unless you want to buy a used cylinder bank).  The pistons generally cost more than the rings, so...Sounds like your cheapest route would be to bore out to 65mm and use your ART pistons.  Do you know what rings you need to run with them?
What kind of compression ratio do the ART pistons generate?
Alternately, the CBX ran 64.5mm (giving you 823ccs) they had a higher dome, but if you had an F2 head to run...

Whatever, I know nothing.

Kenolds
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Offline crazypj

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Re: Stuck - assistance needed (pistons??)
« Reply #8 on: September 03, 2009, 12:56:15 PM »
CBX is 4 valve/cyl, will need to re-machine valve pockets

PJ
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