Diagphram Clutch spring specs...
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Seasoned HDF Member
Joined: Mar 2010
Posts: 21,027
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From: Poolville
Diagphram Clutch spring specs...
I have an SE spring 37951-98 which is .078" thick @ #385 and I know the 37871-98a is .071" thick @ #320 but I'm looking for the thickness of the CVO/Police pink spring 37807-03 That is supposed to be #365.. If someone could give me that dimension, I would appreciate it.. Thanks.
Next question, I thought I was running the SE spring with my last build of 125/130 with the energy 1 extra plate kit and never noticed any slippage but when I opened the primary, the fluid wasn't as clean as I thought it should be with a small hint of fluid burn but no evidence on the frictions or steels of slippage, they looked good. So Now that I'm upgrading the clutch to an Evolutions Industries Diaphragm Clutch that has 2x the surface of frictions and steels Do I need to use the SE spring Or can I use the stock spring? It would seem to me that I can use the stock spring because the 2x increase in clutch application.
If not I will probably find a pink spring which is supposed to be lighter than the SE but heavier than the Stock.. Thanks..
Next question, I thought I was running the SE spring with my last build of 125/130 with the energy 1 extra plate kit and never noticed any slippage but when I opened the primary, the fluid wasn't as clean as I thought it should be with a small hint of fluid burn but no evidence on the frictions or steels of slippage, they looked good. So Now that I'm upgrading the clutch to an Evolutions Industries Diaphragm Clutch that has 2x the surface of frictions and steels Do I need to use the SE spring Or can I use the stock spring? It would seem to me that I can use the stock spring because the 2x increase in clutch application.
If not I will probably find a pink spring which is supposed to be lighter than the SE but heavier than the Stock.. Thanks..
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Seasoned HDF Member
Joined: Mar 2010
Posts: 21,027
Likes: 7,549
From: Poolville
I called my local dealer for the police diaphragm spring and it currently is not available.. It's on back order till the end of June, so I decided to go to eBay and I found one that wasn't bad, $30 delivered. It's listed as brand new and you can't see any of the retaining ring lines on the diaphragm like you normally would have on a used one. So when it gets here I'll get it installed and see how that feels.. I'll also list the thickness and how much clutch release I will be able to get with both the 18° and 21° ramps for those that are interested.
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Seasoned HDF Member
Joined: Mar 2010
Posts: 21,027
Likes: 7,549
From: Poolville
So the Police (pink) spring came in today and I was able to get it installed.. The thickness of the spring is the same as the stock spring @ .071" but it did take 3 more pounds of pressure to pull the Police spring over the stock spring.. SE spring that measures .079" took 3 lbs. more pull than the Police spring.. We'll see how well the police spring holds the power of my new motor build of 117"...
Grand HDF Member
Joined: Apr 2007
Posts: 3,714
Likes: 3,040
From: Brighton, MI
Bob, not sure if any of the following helps. It's a cut and paste from a document on info I found and saved a few years ago. Please double check any info you may use before using...Year Models P/N
99 99 - * ALL 37871-98
01 01 - * ALL 37871-98A
03 ALL 37871-98A
04 ALL 37871-04
with the 06's having the 37882-06
37882-06 has a brown paint mark.
The problem you have with the springs is that they not all are identical
Supposed to be
SE 380 lbs
98 330 lbs
04 300 lbs
06 300 lbs, except as soon as you load it from spec installed height it goes down
37951-98 Clutch diaphragm spring, high performance, is in SE Street Legal Big-Bore (EFI) Stage 2 Kit
37951-98 Clutch diaphragm spring, high performance, is in SE Twin Cam 103B C.I. Stage Kit
37807-03 CVO Clutch spring Yellow dot / Pink dot .381" Free Height
37871-98A 2003 Spring Yellow dot .398" Free Height (FSG does not agree 10.5mm .413")
37871-04 2004 Spring Yellow dot / Yellow Stripe .395" Free Height (FSG does not agree 10.1mm .398") .071" Thick
37951-98 SE Spring Nothing .405" Free Height (FSG does not agree 10.4mm .410") .078" Thick
37882-06 06-07 Spring Redish Brown Square / Yellow dot .410" Free Height, 10.4mm .064" Thick
110" and 103" Engine Kits use S.E. Spring P/N 37951-98
37882-06A blue dot (260 lbs/ft) 2006-88", 2007 thru 2010-96"
37871-04 yellow dot (300 lbs/ft) 2004-05 88" and 2010 Limited
37871-98A (320 lbs/ft) 1998-2003
37807-03 pink dot (365 lbs/ft) 2007 thru 2010-103 "Police"
37951-98 (385 lbs/ft) Current SE
And from another source:
37882-06 (117 KgF) 2006-88”, 2007 thru 2010-96”
37871-04 (135 KgF) 2004-05 88” and 2010 Limited
37871-98A (145 KgF) 1998-2003
37871-98 is reportedly the same as above except cheaper, but although is no longer available may still be in dealer inventories.
37807-03 (165 KgF) 2007 thru 2010-103 ”Police"
37951-98 (175 KgF) Current SE
99 99 - * ALL 37871-98
01 01 - * ALL 37871-98A
03 ALL 37871-98A
04 ALL 37871-04
with the 06's having the 37882-06
37882-06 has a brown paint mark.
The problem you have with the springs is that they not all are identical
Supposed to be
SE 380 lbs
98 330 lbs
04 300 lbs
06 300 lbs, except as soon as you load it from spec installed height it goes down
37951-98 Clutch diaphragm spring, high performance, is in SE Street Legal Big-Bore (EFI) Stage 2 Kit
37951-98 Clutch diaphragm spring, high performance, is in SE Twin Cam 103B C.I. Stage Kit
37807-03 CVO Clutch spring Yellow dot / Pink dot .381" Free Height
37871-98A 2003 Spring Yellow dot .398" Free Height (FSG does not agree 10.5mm .413")
37871-04 2004 Spring Yellow dot / Yellow Stripe .395" Free Height (FSG does not agree 10.1mm .398") .071" Thick
37951-98 SE Spring Nothing .405" Free Height (FSG does not agree 10.4mm .410") .078" Thick
37882-06 06-07 Spring Redish Brown Square / Yellow dot .410" Free Height, 10.4mm .064" Thick
110" and 103" Engine Kits use S.E. Spring P/N 37951-98
37882-06A blue dot (260 lbs/ft) 2006-88", 2007 thru 2010-96"
37871-04 yellow dot (300 lbs/ft) 2004-05 88" and 2010 Limited
37871-98A (320 lbs/ft) 1998-2003
37807-03 pink dot (365 lbs/ft) 2007 thru 2010-103 "Police"
37951-98 (385 lbs/ft) Current SE
And from another source:
37882-06 (117 KgF) 2006-88”, 2007 thru 2010-96”
37871-04 (135 KgF) 2004-05 88” and 2010 Limited
37871-98A (145 KgF) 1998-2003
37871-98 is reportedly the same as above except cheaper, but although is no longer available may still be in dealer inventories.
37807-03 (165 KgF) 2007 thru 2010-103 ”Police"
37951-98 (175 KgF) Current SE
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Seasoned HDF Member
Joined: Mar 2010
Posts: 21,027
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From: Poolville
@Yankee Dog
Thanks that all corresponds to everything that I have researched as well Thank you.. I just wish I had a proper tool to check the pull on the spring at the lever.. I think the Pink/Police will do just fine..
Thanks that all corresponds to everything that I have researched as well Thank you.. I just wish I had a proper tool to check the pull on the spring at the lever.. I think the Pink/Police will do just fine..
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,830
Likes: 7,968
From: poway
FWIW free height really don't mean jack since the springs are pretty much constant force. If you look at the springs they are all cut the same pattern and from similar steel will produce the same results.
Road Master
Joined: Feb 2021
Posts: 1,056
Likes: 469
From: Phoenix Arizona
OK,
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
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Seasoned HDF Member
Joined: Dec 2005
Posts: 19,830
Likes: 7,968
From: poway
OK,
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
https://newcombspring.com/Springulat...ng-calculator?
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Thread Starter
|
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,027
Likes: 7,549
From: Poolville
OK,
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
The discussion about springs has got me all "bound" up. I'm in a "bind".
Please help me get "un-sprung" Now that I has used all of the puns...
Seriously.
I understand the N rating on the springs. Is that due to the thickness of the spring, the way it is wound?
What makes the spring stiffer ?
I have stock springs. I did install some "heavy duty" after market... and they did NOT hold. Those springs did NOT have a N rating? My clutch slipped. I still want to put in heavier springs.
TIA
Road Master
Joined: Feb 2021
Posts: 1,056
Likes: 469
From: Phoenix Arizona
I'M SORRY...
You as the OP disn't say WHAT the application was?
I see you sig , maybe its for one of these. How would I know.
And yes, apparently I DON'T KNOW what is being talked about here.
I have a 2107/ 107. I usually always try to mention what bike I am talking about. Cuz, I have a 2002/88 as well.
Sorry.
I'll butt out.