Author Topic: Another clutch question  (Read 2417 times)

Offline taroha10

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Another clutch question
« on: 20.02. 2011 09:14 »
Hi all,
I know this one has been covered before but I would just like some reassurance.
I have a 4 spring Triumph clutch which I have just dismantled for inspection.It had a friction plate at the back and the front which seems to contradict what the parts diagram says.As there are slightly proud rivets at the back of the chainwheel it just dosn't go right in my head that it would have a plain plate running against it, but then they would I suppose also eat into the friction plates aswell.Also having metal to metal on the last outer plate against the pressure plate seems wrong too.
Has anyone done a good few miles with 6 plain and 5 corked plates just to put my mind at ease!
Just incase someone asks if it worked ok before I took it apart, the answer is not exactly.I've had various problems but mainly with drag and getting out of gear .
Cheers to you all for a fab forum!
Mark.

Online bsa-bill

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Re: Another clutch question
« Reply #1 on: 20.02. 2011 09:49 »
Had the same thoughts when I changed mine Mark

six metal and five friction, really says it all if you think about it
Metal first and metal last the book is wrong (see it's not only Haynes)
the last metal plate up against the pressure plate is not a problem as once the clutch is disengaged the metal plates are not driven.
Don't be tempted to put an extra friction plate in first, it won't do anything as it will not get right up to the inner face of the clutch

I also have some of the thinner friction plates that are around, this allowed me six friction and seven metal, seems all right at the moment
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online chaterlea25

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Re: Another clutch question
« Reply #2 on: 20.02. 2011 12:01 »
Hi Mark and Bill,
The number of plates depends on whether the inner clutch drum has a lip to hold the innermost plain plate or not
Later Triumph/ BSA clutches do not have this lip and have a thrust washer on the shaft adaptor, behind the chainwheel.
Then the innermost plate is a friction one
this is fixed by the tongues in the slots and doesn't rotate against the rivited drum
The next plain plate sits against this as there is no lip to hold it

On the earlier ones where the plain plate sits against the lip on the inner drum theres a tendancy for this plate to bow
from the spring pressure, other makers sometimes fit a thick plate in this position!!
The pressure plate turns with the last plain plate  and so there is no relative movement between them

HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline taroha10

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Re: Another clutch question
« Reply #3 on: 20.02. 2011 13:35 »
Thankyou Bill and John for your speedy replies.I have been backwards and forwards from the shed and have decided to go for the plain plate first.The inner drum does have a lip to stop the plate touching the rivets ( can't believe I didn't work that one out )I can see how the back plate could warp but i'll try it and see.
When I took it apart it had a friction plate first.I have some new friction plates and have dressed  the drum a little to remove burring.
It was hard to get the old friction plates out but the new ones slide in a treat so that has got to be  an improvement  for a start.
Now I have 6 plain & 5 friction and will report back.
Thanks again guys.
Mark.

Online bsa-bill

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Re: Another clutch question
« Reply #4 on: 20.02. 2011 19:20 »
Wayhay John - I didn't twig the difference as I have obviously the earlier one on the RGF, the other A10 (Flash) is 61 so will have the later one but I have not taken that apart as it's performing ok

Nice one - you never stop learning here
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online chaterlea25

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Re: Another clutch question
« Reply #5 on: 20.02. 2011 22:38 »
Hi Bill
The inner drum without the lip is I believe a 60's/70/s item
SRM used to do a kit with the "modded" inner drum and shaft adaptor with thrust washer for the pre unit models
I think it might be standard setup on the late(r) A65's and later Triumphs

HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline taroha10

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Re: Another clutch question
« Reply #6 on: 22.02. 2011 12:15 »
Well it's  good and bad news. The orininal problem of drag has not changed to slip.
I can now sit with the engine running and take the bike in and out of gear, but even with the adjusters nearly wound right home,the kickstart slips sometimes and under power there is slip. I havn't changed the springs yet but they seemed alright before.
As I said before, when I dismantled the clutch it had an extra friction plate at the back. I wonder if it is worth trying a second plain at the back .I just can't get my head around the consequences of this! Help!!!
Cheers .Mark

Offline taroha10

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Re: Another clutch question
« Reply #7 on: 22.02. 2011 12:27 »
Almost seconds after my last posting it occured to me that now with a plate less the clutch springs are relaxing after years of extra tension .Would one plate difference have this effect?

Online chaterlea25

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Re: Another clutch question
« Reply #8 on: 22.02. 2011 12:45 »
Hi Mark,
As you say the clutch springs can get tired, Another possibility is that the clutch plates are contaminated with oil
did you oil them before assembly?? DONT!!
If "car" type multigrade was used in the primary a lot of these oils have slippery additives which cause problems.
ATF or 10/30 motorcycle oil is what I find works
I can recommend fitting these clutch springs from SRM, stock code 57.1560 (T120) These give a nice light clutch and no slip *smile*

HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline taroha10

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Re: Another clutch question
« Reply #9 on: 22.02. 2011 17:12 »
Thanks again John for your speedy reply.Have just gone and got some new springs ( I think they are T140 ) to try.
I didn't oil the clutch but must confess that I  was short on ATF which I normally use and topped up with multigrade (bad Boy).
Have drained this out and will try new springs tonight with fresh ATF.
If it still slips I will try adding the extra plain plate at back of clutch.
Right, I'm off to the shed.
Cheers. Mark.

Offline LJ.

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Re: Another clutch question
« Reply #10 on: 22.02. 2011 19:09 »
ATF might be good but it don't half leak out if your case joints are poor. I use Halford 20/50 in all my bikes primary chaincases with good results.
Ride Safely Lads! LJ.
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1947 BSA M21 600cc Girder/Rigid-Green
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Online trevinoz

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Re: Another clutch question
« Reply #11 on: 22.02. 2011 20:17 »
Mark,
             I think you will find T140 springs too heavy. They are for a three spring clutch and are a lot stiffer than four spring types.
                      Trev.

Offline taroha10

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Re: Another clutch question
« Reply #12 on: 23.02. 2011 10:44 »
Well thanks again for all your replies.
Took clutch apart yesterday,tried an extra plain at back but there was no room.Have cleaned it all up, added new springs and refilled with ATF ( a test for the chaincase seal).I have had to screw the adjusters fully home but went for a test this morning (in the rain)and it now all seemes ok.
The springs don't seem too heavy ,I can select neutral at a standstill, and so far I don't think there is any slip.
It will be good to see how it is after a long run.
Cheers again for all the input.
Mark

Offline Guy Wilson

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Re: Another clutch question
« Reply #13 on: 06.05. 2011 15:58 »
Its reassuring to read the book is wrong! I'm fitting a 4 spring clutch with 6 plain plates and 5 corked that I took off an early 60's  A10. I'd assumed, wrongly, that it was later clutch and original to the later bike. It seems from what I'm reading its an earlier clutch and probably what was originally fitted to the 1955 Gold Flash I have.
It would have confused Sherlock Holmes...

Online chaterlea25

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Re: Another clutch question
« Reply #14 on: 06.05. 2011 22:58 »
Hi All
Guy,
Yes late A7/10's were fitted with the 4 spring clutch from the factory

HTH
John
1961 Super Rocket
1963 RGS (ongoing)