Author Topic: clutch springs?  (Read 755 times)

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Offline Don R

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clutch springs?
« on: March 26, 2025, 10:32:09 PM »
  The Rat Race bike has reeeeal stiff clutch springs. They need to go, what's available these days?  Are old stockers the go to spring? I see Barnett, Vesrah, EBC, and even
Sirius $9.99 delivered on ebay. 
  Does anyone have a preference for mostly normal street riding?
« Last Edit: March 26, 2025, 10:36:33 PM by Don R »
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Offline PeWe

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Re: clutch springs?
« Reply #1 on: March 27, 2025, 01:50:49 AM »
My K2 has Barnett CB750 springs. Middle number -56-
Work fine, not hard for clutch fingers

My K6 with  +100whp must use the  stiffer Barnett with middle number -66-
They are for the smaller CB's.

Slip with the weaker Barnett springs despite glass beaded metal discs, later clutch from an F2. Tested twice.


These made my clutch fingers really tired. It helped to lubricate the clutch cable with  teflon cable spray.

Next step was "dog leg" type of  clutch lever,  more comfortable.

Both my bikes got them for clutch and brake.

GP style here https://vintagecb750.com/products/clutch-lever-gp-style

Stock type of clutch lever under the dog leg type that is more comfortable, flatter closer grip.

The golden spring, the weaker for CB750. -56-
Black the stiffer with middle number -66-


« Last Edit: March 27, 2025, 10:54:01 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline HondaMan

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Re: clutch springs?
« Reply #2 on: March 27, 2025, 09:41:35 AM »
  The Rat Race bike has reeeeal stiff clutch springs. They need to go, what's available these days?  Are old stockers the go to spring? I see Barnett, Vesrah, EBC, and even
Sirius $9.99 delivered on ebay. 
  Does anyone have a preference for mostly normal street riding?

The normal Vesrah or OEM springs work fine for me up to 80 HP. Does the bike have OEM clutch plates, or something else?
See SOHC4shop.com for info about the gadgets I make for these bikes.

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Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
Link to My CB500/CB550 Book: https://www.lulu.com/search?sortBy=RELEVANCE&page=1&q=my+cb550+book&pageSize=10&adult_audience_rating=00
Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline Don R

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Re: clutch springs?
« Reply #3 on: March 27, 2025, 10:34:10 AM »
  The Rat Race bike has reeeeal stiff clutch springs. They need to go, what's available these days?  Are old stockers the go to spring? I see Barnett, Vesrah, EBC, and even
Sirius $9.99 delivered on ebay. 
  Does anyone have a preference for mostly normal street riding?

The normal Vesrah or OEM springs work fine for me up to 80 HP. Does the bike have OEM clutch plates, or something else?
  It's not likely over 80 HP, but it is a K1 ported and cammed 836 with Mikuni carbs. It has a set of frictions that were advertised as oem Honda but when they arrived, they were obviously not. The friction material and adhesive were sloppily applied, and I had to clean the tabs off to use them.  So my answer is that they are likely Chinese junk. (Not the boat) The steels were sanded with a DA. It does have a newer clutch, basket etc. in it with a later cover.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline PeWe

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Re: clutch springs?
« Reply #4 on: March 27, 2025, 11:03:47 AM »
I used Cruzinimage low priced clutch plates with 836cc, 80whp on dyno. K6 clutch, no double metal plate. Glass beaded metal discs.
Those plates work fine despite made in China.

My almost stock K2 has a K2 set. 58whp a few years ago. Runs better now, maybe a little more at top.
61.50 392 CI pistons.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Don R

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Re: clutch springs?
« Reply #5 on: March 27, 2025, 11:14:30 AM »
 It does have Magura levers, the collections of old parts that I bought out had some really nice finds in them. I'm sure that the sellers have some level of remorse now that I've made use of what they didn't.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.