4 or 6 spring clutch

[chaterlea25]

Hi JHG,

My last A10’s thirty years ago had a triumph clutch with a conversion spindle. I have not heard this anywhere else so I am wondering if anyone else has heard of this or if I was mistaken. Good light clutch.

Yes,
 The Triumph type clutches are available from quite a few spares dealers
You will see a big difference in price on them due to some being fitted with inferior plates /chain wheels etc
No point in wasting money on cheap sh!t
Then you will need to address lining up the primary sprockets as well
https://www.a7a10.net/forum/index.php?topic=9646.msg70166#msg70166

John

[morris]

My last A10’s thirty years ago had a triumph clutch with a conversion spindle. I have not heard this anywhere else so I am wondering if anyone else has heard of this or if I was mistaken. Good light clutch.

There’s the perfect description of the 4-spring clutch 

[Slymo]

I've got the original six spring clutch on my 58 Super Rocket. I had to replace the centre and put new springs in it. I also made a new silver steel push rod with hardened ends. So far it works very nicely. Not the quickest tool but quite a smooth take off, no signs of slipage and light enough in operation. if I were racing the bike I might be looking to change it but for my purposes it is fine.

[berger]

I use a 6 spring the imported centres are crap-- made from butter, I found this out years ago by the bike destroying them. you can cut them up with a Stanley knife. the originals glide a file off them. I lost the original but in later years got one and fitted it. they have nice reinforcing inside sort of triangular shaped. my bike gets errr thrashed , it doesn't slip it doesn't drag and engages neutral at stand still . admittedly  pulling the leaver in enables me to break brazil nuts between my finger and thumb at chrimbo

[Topdad]

my present bike , 53 yrs ago had a 6 spring clutch, I nearly set light to her . A friend made an adaptor to take a 4 spring Triumph cluctch and bingo really smooth ,no slip and neutral selected when required.

[jhg1958]

I am glad I asked.  It seems a 6 spring clutch when working well, is a thing of joy.  The four spring clutch is obviously better.  Given some arthritis in my hands I feel a new 4 spring clutch is the way forward.

Thanks for all your replies

John

[scotty]

I installed an SRM 4 spring clutch to replace my 6 spring set up
Excellent quality and fit

[berger]

I have not been to the pub, I know I have said a lot about my 6 spring clutch being the dogs b****cks because it really is BUT!! I got a lot of bits for basically well below asking price and somethings amongst the bits are parts for a four spring which I might as well use on the neglected building a berger thing.. my problem is there is an assortment of BITS!. is there anyone on here who knows ----- what the spring and cup lengths are ?and how many plain and friction plates fit on the clutch centre that has the lip on it and no cush drive in it.  there is another clutch centre with the rubbers sandwiched into it but I want to use the hollow one so need a bit of knowledge from you chaps. the drum is 57-1549, the centre is 42-3235. I think I start off with a plain plate is that correct? mainly the cups and spring lengths are     here is a spare 6 spring I re-corked years ago when a kind chap gave me a bag of corks after I spent loads of money on NOS corks that I put in the  chainwheel on betsy beezer

[chaterlea25]

Hi Berger
A Google shows 42-3235 advertised as suitable for A10 ??? But advertising is full of bullsh*t
Can you measure the depth (thickness) of the drum? and I can compare tomorrow
Thinner ones were fitted to earlier model Triumphs
The chainwheel you have (depending on where it came from?) may have the slots all the way to the inner edge of the drum or maybe there's a step there?
Do you have the mainshaft adaptor for fitting to a BSA?
The SRM adaptor if used with a thrust washer and a drum with full depth slots can accommodate a friction plate fitted into the back of the basket (or the slots can be filed deeper)
This if used with an inner drum without a lip or if the first friction plate is machined out to fit over the lip
This allows the spring pressure to work across the entire plate surface rather than the pressure trying to bend the first plain plate that is only supported by its inner edge

Clutch spring thimbles are 40mm according to SRM (3 and 4 spring)
http://shop.srmclassicbikes.com/product/spring-cups-3-spring-clutch-also-571931

T120 clutch springs work well 57.1560 on the 4 spring. beware of the heavier 3 spring type that will make the clutch very heavy
http://shop.srmclassicbikes.com/product/t120-clutch-spring-4-spring-also-t90-t100-a7-a10

There is also a modern 7 plate conversion that has good reports from the T140 boys that uses thinner plates
https://www.ebay.co.uk/itm/TRIUMPH-7-PLATE-CLUTCH-CONVERSION-1963-83-TIGER100-TR6-T120-TR7-T140-BONNEVILLE/131093079355

There is no such thin as a straight answer
John

[berger]

charterlea25 john thanks for reply I have added some photos but don't bother yourself too much because I think I have a mash of bits that I will take to TMS Nottingham and get this sorted ready for the project. the two inner drums in the pictures are both a tad over 38mm deep. I did the same test as you have on a pattern adaptor and a genuine one and got 11mm of thread on pattern and 15 on genuine one. I have cups at 35mm long and springs at 50mm/ 40mm and 35mm

[berger]

this doesn't look right

[berger]

with the rubber cush drum the plate still wants to jump off

[berger]

this is the chainwheel

[berger]

hahaha pillock!!!! told you lot i'me a loon SUSSED it I was looking at things not being in situ with the rollers and all built up aaannnd the morris hate/morris  mmmm is on the road with a gearbox bearing on its way out no peace for the wicked so I am going to the pub! thankyou for listening ps my excuse is I didn't know anything about 4 spring clutches but I do now

[duTch]

 

....« Reply #26 on: September 30, 2019, 23:17:52 »

    Quote

with the rubber cush drum the plate still wants to jump off

 If we looking at excess clearance on the plate ID-centre hub, I can't see that it matters so long as the outer tabs engage ok- they'll centre it