Clutch Spring Length confusion - some bits sorted

LTGTR

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I need to buy clutch springs for my 77D. (Standard 7 plate - short springs)
Researching the forum was a bit confusing (to me) and whats available is also a bit confusing - looking for some clarification.
Mikes sells 2 kits for the 650 :
Part number 39-6506 - I have a set of these on hand and they are approx 41mm long.
Part number CSK14 - these are EBC - and if you refer to the email below - they are also approx 41mm long.
Research on the forum tells me the OEM/correct lengths are:
Up to approx 1979 - approx 37mm long
After approx 1979 - approx 41 mm long
Does this mean I am expected/should/could be using the longer 41mm springs in place of the 37mm ones ?
If this is the case, does the fitting of the 41's instead of the 37's mean the result would be like fitting heavy duty ones ( extra 4mm of spring to compress).
Are Mikes being lazy and just palming of the same size for both the 6 and 7 plate clutches.
To find out what is available I sent an email to EBC asking for the lengths of the springs that fit Yamaha XS650.
Refer to email below which clarifies things from EBC.
I would be interested in advice/direction from the forum.
I hope the info from EBC helps someone.
Regards - Ray.

Copy of my email to EBC
Dear Sir/madam,
I have a 1977 Yamaha XS650 Motorcycle.
There seems to be a lot of confusion about the correct length of clutch springs for this model.
Up to approx 1979 the correct length of the clutch springs is approx 37mm.
After approx 1979 the correct length of the clutch springs is approx 42mm.
You sell 2 kits for the Yamaha XS650 - CSK002 and CSK014.
Could you tell me the length of the 2 kits that you sell.
I understand your website shows which kit is recommended, but I want to know the actual length of the springs in each kit please.
Also, can you tell me where I can buy these in Australia - if I cant buy in Australia, what would be the delivery cost direct from you.
Thanks for all your help,
Regards Ray Kairl.

Copy of Reply from EBC.
Good morning Ray, I hope you are well.
That’s right the kits both have different length springs.
CSK002 = 35.90mm springs
CSK014 = 41.35mm springs
@EBC BrakesDirect please can you advise Ray on purchasing.
Please don’t hesitate to ask if you have any further questions on the kits.
Kind regards
Henry Payne
Technical Advisor
01604 583344
 

gggGary

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Does this mean I am expected/should/could be using the longer 41mm springs in place of the 37mm ones ?
Using both longer and heavier springs I would be watchful of coil bind before the design distance of plate separation by the worm assembly is reached.
 

DogBunny

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