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Discussion Starter · #1 ·
On my Bomber - How does one remove weight from a stock Honda piston ? With ribs on the underside of the piston crown and no blocks on the pin boss, where would one take off material ?

One piston is 5 grams heavier.
 

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Sensei
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Balancing a piston for 5 grams is useless UNLESS you are certain the total reciprocating mass will end up EXACTLY the same..... Did you weigh the con rods?..... Of course not....Gudgeons?....Ring sets?..... Balance the crank assembly to 100%?.....
I'd be happy they're that close......
However, IF I HAD to remove some weight, I'd gently use a 1/8" ball burr on the underside (inside) of the dome gently thinning the ribs OR trim the sides of the skirt....(enlarge the oil ring holes a tad or chamfer the insides ?)
You could probably remove 2 grams just polishing the piston....
 

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Discussion Starter · #3 ·
Re: Piston Weight Emblance Cure ???

66Sprint said:
Balancing a piston for 5 grams is useless UNLESS you are certain the total reciprocating mass will end up EXACTLY the same..... Did you weigh the con rods?..... Of course not....Gudgeons?....Ring sets?..... Balance the crank assembly to 100%?.....
I'd be happy they're that close......
However, IF I HAD to remove some weight, I'd gently use a 1/8" ball burr on the underside (inside) of the dome gently thinning the ribs OR trim the sides of the skirt....(enlarge the oil ring holes a tad or chamfer the insides ?)
You could probably remove 2 grams just polishing the piston....
Gudgeons ? LOL.....IMO 5 grams is a significant emblance.
 

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Sensei
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Gudgeons?...You probably call them wrist pins...LOL.....(easier to remove the smaller amount of steel)
Again, a 5 g (imbalance) heavier piston means nothing if the con rods are 10g off ...and how do you know which con rod is heavier (to attach the lighter piston to) or even IF one IS of differing weight if you didn't weigh them?
Perfect static balance requires ALL components be weighed and adjustments made based on the compilation of ALL those results.....
I have only ever done this once... to help set the bike up for Daytona...
 
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