Author Topic: 6 spring clutch sleeve (Quality of parts)  (Read 1726 times)

Online chaterlea25

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6 spring clutch sleeve (Quality of parts)
« on: 26.03. 2010 12:01 »
HI ALL,
Slightly off topic but relavant all the same!!!!
I am in the final throes of completing the rebuild of a plunger framed B32
When it came to refitting the clutch centre sleeve I found it was wrong and did not fit on the taper but went on in till it hit the gearbox sprocket nut???
I had another centre in a box of bits but this would only fit on about half way on the taper (sprockets way out of line)

A friend was going to Vale Onslows in Birmingham so he bought a new centre sleeve and some more new bits for the clutch as well including a new sliding plate.

When I got the parts I found that the centre sleeve was undersize by 0.012 where the inner bearing fits  *sad2*
The bearing inner is 1.375in.ID and the sleeve 1.362 OD
I rang the shop who said send it back, when I rang some days later to see whats happening I was told that all the ones he had were undersize *ex* *ex* *ex*

I then ordered one from Draganfly, sending a note with it to check the dimension where the bearing fits
It arrived this morning and is exactly the same dimension as the other *sad2* *sad2* *sad2*
So I phoned them up and asked WTF's up

I was told there is only one supplier of these and they do not listen to the retailers or customers complaints
In other words "there you are, now sod off!!"

I just got the bikes owner to phone C&D to check their stock and they are under size as well *ex*

The sliding plates are another issue the hole is nowhere near round (circular) or anything like a good fit over the spiral collar *eek* *eek*
I am going to send the second one of these back as well and machine a new centre piece for the original sliding plate

I have found its not really feasable to fit a four spring clutch to the plunger models, I previously bought what was supposed to be an adaptor for a "B" series but it was almost identical on how far it fits onto the gearbox mainshaft
as the "A" adaptor. so the sprockets wind up  out of line

Solutions anyone???

Regards
John O R


1961 Super Rocket
1963 RGS (ongoing)

Offline Beezageezauk

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #1 on: 26.03. 2010 15:49 »
Hi John,

I've had much the same problem when I was building my latest A10.   It came as a basket case so I basically used what parts I had and when the bike was up and running I found that the primary chain was catching the thin bolt heads that hold the slider onto the inner primary chaincase.  This, in turn, was caused by the clutch centre sleeve going too far onto the mainshaft taper.

The most annoying thing was that I hate doing the same work twice, especially when it's not my fault.  Still, I know what to look out for in the future!!

In the end I tried several second hand sleeves onto the shaft and measured the amount of thread that stuck out of the end and was amazed at the variation.  Some of these 6 spring clutches use a different number of clutch plates depending on what model they were for, and I wondered if that caused the variations in the depth of tapers.

Obviously, this doesn't answer your problem because when you order a particular item you expect it to be fit for purpose.  I always try to use original parts where possible and have found lots of pattern parts to be ill-fitting.

Still, we battle on against adversity.  Is this what makes the old bike game more interesting??  Probably not!!

Beezageezauk. 




Offline muskrat

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #2 on: 26.03. 2010 19:38 »
G'day John,
               a real pain in the ass. Would it be possible to build up the bearing surface with either metal spray, hard chrome or weld and grind back to correct size.
If all the parts retailers sent them back they might take notice.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online chaterlea25

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #3 on: 26.03. 2010 21:50 »
Hi All,
As a follow up todays developments are,
C&D Autos had a note in their box of sleeves saying "Do not sell these" the other partner who knows about these wasn't there today, they said to call Autocycle engineering

Autocycle said "Yes we know there is a problem" we are trying to come up with a solution?? undersize bearing race's???
Anyway another wait to see if theres going to be a resolution!!

Muskrat I did think of metal spraying or hard chroming but it would mean remachining the splines again
I'm thinking of plating the bearing inner if no solution is found??

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

Online trevinoz

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #4 on: 26.03. 2010 23:10 »
John,
             I bought 2 sleeves from C & D a couple of years ago and had the same problem.
I had a toolmaker have a look at them and he found that the taper angle was incorrect.
He managed to turn one to the correct taper, stuffing his tools along the way because of the hardness and keyway.
The second one didn't fare so well.
Apparently the taper should be 3` 40" by calculation. [I think, it's been a while since it w2as done.]
   Trev.

Offline dpaddock

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #5 on: 27.03. 2010 15:36 »
Note that there were five mainshaft numbers listed by BSA for pre-unit A and B models (although the B range had its own for 1946-48 according to Bacon's "BSA Singles Restoration", page 79).

Re the shaft taper, I never measured it with an optical comparator - the one time I had the opportunity, I used it for something else - but several diametral measurements I've made indicate 4 degrees even (half angle). In any case, lapping the taper surfaces together is a good way to ensure a tidy fit up.

David
David
'57 Spitfire


Offline BSA_54A10

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #6 on: 27.03. 2010 20:35 »
And there are a dozen or so clutch sleeves.
With a few exceptions BSA used the same tapper on the end of their main shaft from 1910 till 1972.
To get rough alignment they varied the size of the tapered hole in the sleeve.
Fine adjustments being made via the spacer behind the engine sprocket.
The end result is that any 6 spring clutch will go onto any main shaft (except the splined plunger ones ) but it won't line up unless the tapered hole is the correct size.

One of the "fun" things about having a shed full of piles of boxes roughly equating to a few dozen Beesas is that you get to play swapsies when you desperately need a bit at 1 am the morning of a major event so at one time I rode the A10 with an M20 single spring clutch in there, worked reasonably well if you were careful with the right wrist & foot. When you are set up like this you notice things like main shaft tapers. The B2 ( round tank ) will have an M20 single spring clutch with a shorter lighter spring, one set of plates and no top hat ( try & find round tank parts ).

Now as for the inner bearing race, It is ( or was) a standard size.
Down here we don't have the luxary of calling 1/2 dozen different suppliers so when mine was cactus it was down to my favourite bearing supplier with check book in one hand & bottle of scotch in the other ( you can not expect them to spend hours trolling through bearing cactalogues just for the sale of 1 bearing to a very irregular customer ). He found a standard double row caged ball race with the correct ID ( remember it is an interfearence fit )  I bought two took them home, cut off the outer race and cage with the Dremel tool ( god I love that machine) and I was off to the second All British Rally ( about 1976 ).
The bearing was still in there when I went belly up and had to sell the bike.
 


Bike Beesa
Trevor

Online trevinoz

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Re: 6 spring clutch sleeve (Quality of parts)
« Reply #7 on: 27.03. 2010 23:12 »
David,
            The bloke who remachined my hub measured a main shaft and calculated the angle using good old trigonometry.
The hub fits ok, had to lap a little. The stuffed one has the correct angle but too much diameter.
The hub should really have been ground to size but it's difficult to find someone who can do it.
The thread on the main shaft needs to protrude 3/4" when the hub is fitted.
  Trev.