worntorn
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- Dec 22, 2006
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lcrken said:Fast Eddie said:JS Carrillo conrods vs stock, the carrillos are simply things of beauty! Overall they are slightly heavier than stock (only slightly), but the little end is lighter.
The bike is looking great, and should be really impressive when finished.
Please don't take this as a criticism, but I just noticed what you said in the original post about the weights of the rods, and thought I ought to correct it.
The small end on Jim's Carrillo rods is not lighter than the small end of stock rods. It is significantly lighter than the standard (steel) Carrillo Norton rod small end, but not than that of the stock aluminum rod. The small end weight of Jim's rods is 105 grams, where a standard Carrillo is more like 135 grams, but the small end of the stock rod is only 75 grams or so (75 - 78 on the ones I've measured). FWIW, the only aftermarket aluminum rods for Nortons that I've measured (from Kenny Dreer) were slightly heavier at the small end than Jim's, at 110 grams. Jim's setup gets it's lighter reciprocating weight from a lighter piston and lighter pin, not from the rod.
On total rod weight, the Carrillo rods, both Jim's and the standard Carrillos are heavier than the stock rod. A stock 750 rod weights around 390 grams, Jim's Carrillos weigh 431 grams, and a current standard Carrillo steel rod weighs 472 grams (earlier ones weighed as much as 512 grams). The additional weight is mostly in the big end, which is rotating weight, and doesn't affect vibration much, so I don't consider the total weight differences to be very significant.
None of this is a criticism of Jim's kit. He never claimed his rod small end was lighter than the stock rod, just lighter than the standard Carrillo and some aftermarket aluminum rods. He worked pretty hard to convince the Carrillo engineers that it was safe to make the small end that light, and the rod is indeed a thing of beauty. I've seen titanium rods for Commandos that were heavier at the small end than Jim's.
Ken
Hi Ken
''The additional weight is mostly in the big end, which is rotating weight and doesn' t affect vibration much..."
Isn't the additional weight mostly in the small end and should be considered reciprocating weight?
If the stock small end is 35 grams lighter than the JS, then that is 35/41 or eighty five percent of the total weight difference between stock and JS rods.
Glen