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Discussion Starter · #1 ·
I found yesterday that one of the pistons was chipped and damaged so I will have to replace it. I was just wondering if anyone had a good source for pistons. I know there is some on eBay and other places. I also don't know what size bore to get.

Can I get a meter that will measure accurately enough or should a shop measure it for me?

'72 CB350K
 

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Sensei
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Piston oversizes are cast or stamped into the crown.... First, you'll need to know what the current size is and if the cylinder is in need of boring, or if a quick hone will clean it up... Once you know the bore size (cleaned-up), you can figure on the piston size needed.... and if more boring will be required to fit that piston....
 

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Discussion Starter · #3 ·
cleaned the pistons off some and couldn't find any markings? This is only a photo of one of the pistons, but the other has the same markings.



I thought the markings would be stamped on the top.? The only thing on the piston, is on the side it says "ART" and then a "7." does that mean anything about the size? Is that a 7th bore?

Any tips?
 

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Well Art pistons are aftermarket so it's definitely had a top end job, but I've never dealt with them personally. Someone here will have more information soon enough on the size.

GB :mrgreen:
 

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Bird76Mojo said:
Well Art pistons are aftermarket so it's definitely had a top end job, but I've never dealt with them personally. Someone here will have more information soon enough on the size.

GB :mrgreen:
That may not be the case at all - this shows a piston from a CB200, with less than 2,000 miles on it, undoubtedly the stock piston, it was the standard size (no doubt about it).
It clearly has "ART" stamped, plus a number.
Not clear on what the number actually means - it's been suggested that it may indicate a factory batch number or something like that.
I have seen ART on a number of stock pistons from various models......

Only way to know its size is to measure it.

 

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Sensei
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I agree with Bill.... ART was a supplier for the Honda factory pistons....The "7" or whatever is a Batch number, mold number or something similar, and does not indicate size. ..... A micrometer measurement is the best way to positively "size" the piston, but in general, pistons with NO MARKINGS on the crown are STD size..... The first oversize would have .25 stamped into it, being 1/4 mm larger in diameter than stock.....A .50 would be second over, etc.....However, these markings are sometimes very faint, and the crown has to be REALLY clean to read them........ Steve
 

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I never would've guessed that Honda would actually use another manufacturer's pistons in their bikes? I've never heard of this in my life, and would tend to disagree if I had more experience in this area. BUT obviously to figure that out, it would take someone that has owned the bike since BRAND NEW, to tear it down and look to be sure. Every single Honda I've ever torn down had an OEM Honda piston in it...


I stand corrected. As usual. :lol:

GB :mrgreen:
 

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Discussion Starter · #8 ·
From what I've seen inside the motor and from the tear down there has been someone inside before me. I don't remember how many miles there were on the bike but it was a lot. These are probably not stock pistons but I'm not sure. I guess I'll take the pistons, and cylinders to a shop and have them measure them, and then I'll order the proper ones.

Should I take them to a machine shop or a motorcycle shop?

Also where should I buy them from?
 
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