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Author Topic: What do these do?  (Read 2132 times)

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Offline KB02

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What do these do?
« on: December 04, 2007, 05:33:57 AM »
According to the Parts fiche they are called "Rubber Insert." The part number is 12620-286-000. But, what function do they serve?



I'm just curious.
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jsaab2748

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Re: What do these do?
« Reply #1 on: December 04, 2007, 05:51:15 AM »
they keep the fins from making noise. seriously :)
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Offline rbmgf7

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Re: What do these do?
« Reply #2 on: December 04, 2007, 06:27:04 AM »
i just figured they were vibration absorbers to prevent the fins from fatiguing and breaking off.
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Offline Steve F

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Re: What do these do?
« Reply #3 on: December 04, 2007, 06:38:49 AM »
Quote from: gearbot on December 04, 2007, 06:27:04 AM
i just figured they were vibration absorbers to prevent the fins from fatiguing and breaking off.
ditto
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Offline 754

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Re: What do these do?
« Reply #4 on: December 04, 2007, 07:37:05 AM »
They keep it quieter, actually a high frequency preenging noise, I think.

Run headers it will go away... ;D
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Offline bozo4onion

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Re: What do these do?
« Reply #5 on: December 04, 2007, 08:12:38 AM »
What? They don't keep melted fins from drooping after a good thrashing?
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Offline Jonesy

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Re: What do these do?
« Reply #6 on: December 04, 2007, 10:07:00 AM »
Pretty much everybody covered it. At certain engine RPM's the frequencies created match the resonant frequency for the fins, causing them to vibrate and make a ringing sounds. The rubber slugs stop this.
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Offline SteveD CB500F

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Re: What do these do?
« Reply #7 on: December 04, 2007, 10:34:48 AM »
Do you remember those 1970's GT250s?  They used to ring like a bell!
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Offline 754

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Re: What do these do?
« Reply #8 on: December 06, 2007, 09:29:42 PM »
Either I forgot about this, or I have never seen it before...??

Just got my 970 barrel, it has the rubber donuts and.. 14 setscrews between these all around the block! Looks like they drilled about a 3/16 or so hole through the fins, up to but not thru the bottom one. Then the top  fin or two was tapped to about 1/4 nc. Then a rod was inserted through till it touches the bottom fin, and the setscew went in the top to hold it in place.

Anyone recall seeing this on a motor??
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