Author Topic: Clutch Springs  (Read 2508 times)

Miti

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Clutch Springs
« on: June 18, 2015, 12:06:59 PM »
Anyone got a set of clutch springs..? Preferably new..?

Mine appears to have been fitted with "extra-long" springs (for some reason).

The rest of the clutch is "relatively standard" (Surflex plates) so I've no idea why these were fitted...

The clutch is slipping and there appears to be no other reason why it would do so... All the plates are 3.6mm thick, so well in spec...

Cheers M'dears...

Jeff
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)

Rob B

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Re: Clutch Springs
« Reply #1 on: June 19, 2015, 07:18:21 PM »
Hello Jeff,

I suspect someone just fitted the springs that came with the Surflex Clutch plates which are for a Ducati 900SS, SD, SSD, 860GT, GTE etc. etc. I will check tomorrow to if I have a set of HESKIFF springs which are shorter but heavier poundage I beleive. The Ducati ones are longer but lighter...

Cheers,

Robert
Hesketh V1000 Black/Gold/Gold EN10++
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Triumph 900 Sprint

Miti

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Re: Clutch Springs
« Reply #2 on: June 19, 2015, 10:24:32 PM »
Hello Jeff,

I suspect someone just fitted the springs that came with the Surflex Clutch plates which are for a Ducati 900SS, SD, SSD, 860GT, GTE etc. etc.... The Ducati ones are longer but lighter...

Cheers,

Robert

I think you're right Robert... The Hesketh Manual says the Min Free Length for the Hesketh OE springs is 36mm (replace @ 35mm).  The springs in mine are all between 42.25 and 42.6m...

(Just for ref, they're 13.3mm OD, have 11 active coils and are made of 2mm wire).

If I measured the fitted length correctly, the six springs give a clamping pressure of less than 350 lbf/in...  For a bike as heavy as the V1000 (esp with me aboard) and an 80+ bhp claimed output, I think 450 - 500 lbf/in would be more appropriate...

I hope you do have a set...  :)

Jeff
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)

MICK

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Re: Clutch Springs
« Reply #3 on: June 20, 2015, 11:49:09 AM »
Start working that left hand with the exercise ball Jeff  :-X
A few customers put softer springs in to ease the load on the fingers of the left hand.
We never used Ducati springs ( maybe we should have) but did use the later surflex plates as they have a reduced area which followed one of my modifications which increased the clamping load and achieved a slightly bigger torque radius by moving the clamping area out.
It all helps.
The best result was when we changed to the Triumph lever assemblies which because of the pivot change produced a better feeling and lighter lever.
The mod I only tried out once which failed because I was using a nylatron piston was to fit a bigger piston in the right timing side and was on my list of things to do before I destroyed it all.
The later bigger motor was always close to destroying the clutch and would have needed looking at after more improvements in performance
« Last Edit: June 20, 2015, 11:56:37 AM by MICK »

Miti

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Re: Clutch Springs
« Reply #4 on: June 20, 2015, 11:07:27 PM »
Thanks Mick;

I'm still at the point where I'm trying to find what I've actually got (as illustrated in  this separate topic:

The basic problem is that I don't know what was fitted in the original build of my engine, or what's happened since...

Just now, I'm happy that I have the following serviceable parts:

Clutch Centre
Clutch Basket
Clutch Plates (friction and plain).

There is defintely a problem with the spring boxes (one is worn through, the others don't look 100%).  The set of replacements sent up by Colin are far more robust, but don't fit into the pressure plate...

The springs fitted are WAY longer than the spec in the V1000 manual (42 mm versus 36 mm) and appear to be of a really low rate for such a big engine/clutch...

So... Which are the correct parts..?

At the mo, I'm considering modding the pressure plate to fit the new spring boxes and fitting OE springs, which brings me back to the topic... Anyone got any NOS clutch springs..?

If anyone has a set, but doesn't want to sell, the following details would be VERY much appreciated:


1.  Free Length
2.  Size of Material
3.  The number of active (complete) coils (The fig shown has 7)
4.  The Outside Diameter

Many thanks

Jeff

« Last Edit: June 20, 2015, 11:10:07 PM by Miti »
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)