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Glenn
07-27-2009, 05:56 PM
going 40 over on my 50 pan and just wondering what would the best piston be. I've been looking at KB cast what the opinion of the masters?

flat-happy
07-27-2009, 06:13 PM
i like cast better because the forged pistons always make a chirping sound which means a lot more engine noise---almost sounds like spark knock

bmh
07-27-2009, 07:52 PM
I've been punishing a set of KB hypereutectic cast pistons for about 30,000 miles now. I like em a lot. Much better than those dang forged things. Not exactly the cheapest piston you can buy, but worth it in my opinion.

Glenn
07-28-2009, 04:06 AM
thanks for the replies, I was leaning towards the KB cast

koanes
07-29-2009, 12:26 PM
Something to keep in mind, the KB pistons for pre Evo models can be up to 100 grams lighter than oem or oriental replacements. This will significantly change your balance factor. Not a big deal if you are doing the whole motor and you balance with the KB piston weights.

Glenn
07-29-2009, 03:12 PM
thanks Kyle

anyone have the V Twin part number for the 40 over KB's cast

Chris Haynes
07-29-2009, 08:20 PM
thanks Kyle

anyone have the V Twin part number for the 40 over KB's cast

Look on page 483.
http://www.vtwinmfg.com/Catalog1/VTwinCatalogIndex1.htm

indianut
07-29-2009, 10:16 PM
As far as the weight, I have put brass into a wristpin to compensate for light pistons with no problemsl noticed.

Glenn
07-30-2009, 05:25 AM
thanks for the info to all

Coolbreeze
11-01-2009, 01:03 AM
As far as the weight, I have put brass into a wristpin to compensate for light pistons with no problemsl noticed.

Wow! I have never heard of anyone intentionally increasing the reciprocating weight inside an engine. I would rather drill the weights on the crank to compensate for lighter pistons. A balanced, lighter component engine just has to run better and longer than one with heavy weights that are forced to change direction several thousand times a minute.

Am I missing something?

exeric
11-01-2009, 06:33 AM
I had to add heavy metal to the flywheels in my '69FL. I'd rather add a little reciprocating weight to the wrist pin than drill out, or add metal to flywheels. All of this changes if you're building a stroker, but stock motors can tolerate moderate adjustments.

sidecar
05-05-2016, 10:26 AM
I'm building a '47 FL knuckle with stock bore A.M. Barrels. Neither V twin nor J&P designate their pistons as "knuckle specific" for a 74" bore. I'm told that the pistons for Knucks, Pans and early Shovels are all the same in height from wrist pin to crown? Comments? What brand & forged or cast pistons would you knowledgable guys suggest? Flat-Happy said above that forged pistons were giving him a "chirp". Was this on a flatty or an OHV? Does it matter? Thanks for your expertise.