The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: a10sausage on 25.06. 2009 17:17
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hi folks...i have just removed the primary case on my goldflash and i am popping new plates and springs in.....i got a bit of a shock and found this clutch....is it from an a65...any info would be ok.....the plates and springs went stright in that i bought for a 4 spring version....cheers
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interesting! the basket looks appropriate for an A10 6 spring clutch, but someone must have changed the pressure plate? perhaps you can take three studs off the inside hub of a 6 spring and use this three spring cover? or they may have replaced the hub with a three spring one, but I don't know the arrangement of the teeth in a three spring...
I bet it is only the cover replaced, since your 6 spring plates fit?? someone else with a broader knowledge should be along shortly ;)
very interesting, maybe I will try to find one of these covers after all if it turns out to be an easy conversion! maybe when you have it apart you can get pics of more of the internals?
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the whole clutch is a 3 springer....and the friction plates and pressure plates that i have just put in are for a four spring as i bought these thinking i was going to find a four spring clutch when i removed the primary case cover...i have just installed the plates and springs as the where the same as the ones i have just removed from this 3 spring clutch....i have just test ridden it and given it a good thrashing and its a fantastic clutch...no slip...perfect smooth action......yee haaa!...ps....i am glad i changed the plates as i found the cush drive on the end of the crank had wound out and shed its split pin....i have fixed that as well....phew!
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oh ho! I was just admiring the rest of the bits in the pic, like the extension on the sidestand (man I hate trying to dig that thing out from under my hot pipe with a boot edge) and I noticed your cush drive is stuck! I had a similar issue with mine getting bound at full spring compression. I didn't notice so much in the ride, but once I knew it was like that I had to get it freed up before I was comfortable riding it again...
your nut (which is in good nick, not all beat like most) may have loosened and allowed enough room for the lobes to get stuck, or it could be put together with an incorrect spring? too few turns could allow it to bind, but the right spring should bottom out before the lobes get crossed enough to stick, pointing to a loose nut.
just one more thing to obsess over ;)
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hi snowbeard....spot on observation on the cush drive....its now fixed.....i found its split pin on the bottom of the primary case!
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Snowbeard
it is such an easy mod to the side stand *idea* I x old bolt, 1 X stick welder, 5 minutes job done no more melted boot on the exhaust pipe.
one of the first mods done to the S/R.
Drop it of at Minety and I will do it for a pint *smile*
Richard
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thanks Richard, I could probably try it myself but I have only a 110V wire feed welder? where is Minety in any case?? I'm out in Colorado, near Denver... ;)
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might be on to something...i think it might be a triumph t14o clutch that also fits an a65
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I have to say up front I know little to nothing about this topic, but I am interested to learn and have been trying.
I had thought I gathered that most unit clutches were two or three row chains? are there some that have single row baskets?
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Hope you did that cush nut up really tight! its a common mistake to allow the split pin to do the work of keeping the nut on, hence what happened to your one. I think also that nut has the job of holding everything up to the main bearing or pulling the bearing towards it... someone will explain better I expect. What about the condition of the crankshaft splines? There is a new thread here just started about them.
Great news that the clutch is better, I've heard that it is a good clutch the three spring one and I do believe it is a BSA one. I have in my Big Box of Bits a single spring one that I'm tempted to fit, dunno how it will hold up to the phenomenal power of the A10! *eek*
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Wow!
This is really interesting! My clutch is a six spring, and I have no idea how they managed it but EVERY bolt is bent and stripped smooth.
Does anyone know if this is a possible bolt on, or anything about this conversion at all (like part #s *ex*).
Lee
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This is really interesting! My clutch is a six spring, and I have no idea how they managed it but EVERY bolt is bent and stripped smooth.
*lol* These old bikes hold alsorts of mysterious suprises eh! *lol*
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Snowbeard
Minety is in the deep south west of the UK in a county called Wiltshire very near to where the Famous Cricklade branch of the BSAoc started, I was only joking about bringing it here but if you want to that will be great.
LJ
I do beleive you can fit a tab washer to the cush drive, they fit them on the unit singles but I do not think they have the split pin I think that by the time the nut gets to the split pin you would or should hear the nut rubbing against the chaincase cover, so you are correct in what you say.
"BSA - GOLD STAR cushdrive nut tab washer 65-2521" this is the same part for the b33 which I had in my box of spares so when I did my A10 rebuild I fitted that to the cush drive assy.
Richard
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ha, Richard, be right by then... ;)
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you would or should hear the nut rubbing against the chaincase cover
Ha Ha! But I wouldn't would I? ;) and your right in what you say about the tab washer... *IF* you can get your fingers in between the spring coils to tab it over, its a sod of a job. My M21 has no split pin at the end of the crankshaft and I worry about that sometimes. All good stuff though eh? *smile*
Now Richard... How about a small Avatar photo so we can follow who this 'Minety' guy is, easy to do and i'll follow you through with some help if you need be.
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Hi Boys
SRM do a really nice replacement cush drive nut that you can actually get a socket on instead of those soppy castlations!(Ebay Item number: 270258925803) take a look!
BSA designed that nut especially to come loose and machine away the inside of your primary case (how many have you seen!!).
Well in my Basket case RR i have a two 6 spring clutches and one 4 spring clutch all a bit rusty.
My 67 A65T has a triplex chain and a 3 spring clutch, blowed if i can remember whats in the Bonni
Lee you can get the clutch hub adaptors that convert 6 spring to 4 spring (later type) Picture attached... there normally available on Ebay etc.
I cant make up my mind weather to bother with a belt drive or stick with the standard 4 spring, (which of course there is nothing wrong with standard set up).
Steve
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That cush nut certainly looks neat! and I never knew SRM sold on ebay, thanks for posting that Steve. Looking at the nut... I wonder what the two small holes are either side of the hex? they seem to be threaded, I wonder if this is some locking device?? Think I'm gonna have to save my pennies for one of these, trouble is I have two A10's so which one gets spoilt? :!
(https://www.a7a10.net/forum/proxy.php?request=http%3A%2F%2Fi10.ebayimg.com%2F08%2Fi%2F001%2F00%2F62%2F62d3_1.JPG&hash=a51f022b19222d14cc1b1715eb9423c1186399f7)
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LJ what is avitar?
and you already know what I look like! handsome with a big quiff and slim!!!! I wish
Richard (minety)
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Hi LJ,
Its a problem isnt it! all i can say its a Bloody good job Her in doors doesnt actually find out how much i have spent on what she calls "Rusty old boxes of Crap" .... im mortally wounded by her comments! I think its because i promised her a day out and took her to Kempton Park bike jumble, not my smartest move.
As you probably know im gathering the parts to rebuild my RR, Im buying a bit here and a bit there, peed off that the dam swinging arm will either have to be changed :! or i will have to Mod the original to take the QD hub (Torque arm and Chainguard) Other threads here talking about replacing SW bushes put me right off! (funny enough its a job i have never had to do).
Anyhow this Nut is on the wish list! Nearly every primary case i have seen has marks from this castellated nut coming loose. As you say the crank is pulled up and shimmed onto the drive side by the nut and tension of the Cush drive. As you rightly said this has to be done up Bloody tight (about 4 and a half white knuckles i think) which is a pain to do with a castellated nut theres probably a "Tool" for the job, i could make one i guess. But the SRM one looks nice and they do make nice parts (at a price) by the look of the one on my engine it looks like its been done up with a cold chisel.
SRM and Burton Bike bits and quite a few others sell on ebay now.
Cheers
Steve
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hi folks...i tightened the cush drive nut up as much as possible and then loctited it into place followed by the split pin ....no damage done apart from the inside of the primary case..,that srm nut looks just the job i will buy one of those,has anybody got an idea on clutch id yet,not that it really matters as i know the plates and springs fit for a 4 spring version.....its just amazing how many alterations these bikes get over a 50 year period.
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I hope that is an old photo as if it isn't then you have it a bit wrong the cush drive parts need to be fitted in the lower part of the curve i.e. the spring will be more relaxed when tightened as the two parts ride up when you pull away under spring tension
Richard
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Those splines look good sausage! (Really cant keep calling you that! have you got a proper name like Fred, Horace or summat?) *lol* *lol*
Richard... The avatar is the little picture next to the message. You see my red A10? that is the avatar it makes a person instantly recognisable. You can use just about any picture on your computer or link from a picture in photobucket.
And Steve... Any woman who spends a day looking round autojumbles needs a medal in my book, amazing women! Mine would moan like crazy.
Edit...
Richard... Looking back to the start of the thread the original photo shows the cush nut nearly off having chewed through the split pin. I bet this was the reason the clutch was not working properly as the cush lobes would have been riding over each other. Hopefully and I think this latest picture from sausage would be a photo before he replaced the clutch plates and done up that cush nut. No doubt he'll put us right... and probably tell us his name is Fred too! *lol*
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The threaded holes in the SRM cush nut are to fit a timing degree disc they sell(I want but am too poor)
Andy
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a10 sausage aka Andy...hope that helps,
when i dismantled the clutch i found an interesting mix of clutch plates all correct but just different makes..now when i removed the friction and pressure plates i found that the last plate was a steel pressure plate against a plain steel basket....no wonder the clutch slipped...aaarrrgghhh...anybody out there have any idea on the exact oil amount to be added to the primary case after a rebuild!
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Hi Guys
Yes Sausage Andy you want to check that cush drive lobes, as richard said they should be for want of a better term "Meshed"
Depends on what primary case you have, if you have an old one you take out a bolt and that acts and the oil overflow and sets the level, a newer one has a Nut and drain tube that sets the oil level. Now were going to get into the row about what oil to use!! *smile*
BSA 500 oh right thanks for that! now theres a thought, i guess you could make one, i might look at that if i buy one of those nuts.
LJ i can assure you she didnt want to be ... using her words "Dragged round boxes of rusty crap" dont worry she has never let me forget it!
Steve
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hi steve...lobes fully meshed...all ok now...am i right sae 20 for the case and 250ml of oil
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Hi Sausage!
8 fluid ounces Mate!
Everyone like different oils in the Primary some use ATF
Steve
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I cant make up my mind weather to bother with a belt drive or stick with the standard 4 spring, (which of course there is nothing wrong with standard set up).
Steve
Steve,
Regarding belt drives,I ran a Tony Hayward belt drive kit in my Triumph p/unit for 6 years (12000 miles) and Ive had one in my A10 now for the last 2 1/2 years and 6500 miles. I really like them.Once set you dont have to adjust them they get rid of mechanical clatter and best of all you can run them dry so no oil leaks.Also,The hayward kit uses a modern friction material which enables you to back off the clutch springs .If you use a nylon lined clutch cable you only need 2 fingers to operate the cluch.Actually on the Triumph I could do it with one finger.
Mike
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has anybody got an idea on clutch id yet
Hi Andy,
As far as i know, ( and i`ll probably be proven wrong ;)), all triumph/bsa 3 or 4 spring clutches as fitted to A65`s, t140`s etc, have interchangeable parts regards being able to put a 4 spring single row basket with a 3 spring centre drum, which is what yours appears to be. You may also have a cush drive cluth drum as well as the crank cush drive, which was discussed recently on another thread.
Hope that helps
Richie
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hi flashback....yes i agree with you about the clutch...it looks like you can mix and match the parts....cool!
i have just topped up the oil as to steves chart...i have just been for a run and its perfect.....cheers mate!
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Hi Guys
Glad she is running ok Sausage! nice there is a way to check the oil levels if you have a primary case with a bolt in the bottom it has an oil level pipe inside this gives you the correct oil level if not it will be one of these ...........
Hi Mike uummm thats very tempting, especially as i will probably have to totally rebuild the clutch anyhow i have seen complete clutches new for about 280 probably not much more for a Belt drive.
Richie, Take a took at BBB page http://www.burtonbikebits.net/alloy_clutch_drums.htm at the bottom you will see the A65 and T140 3 spring clutches i cant see the difference. It may be that its a Duplex or Triplex chain my A65 is Triplex, i suspect you have a Single chain version of this clutch basket, yes all the clutch plates are interchangable!
Cheers
Steve
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Looks like they somehow managed to use a 6-spring basket. The friction plates are definitely interchangeable, but the bearing arrangement would have to be tweaked.
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thanks steve for the primary chain case brochure scan...very helpful,hey you never know this 3 spring clutch might even become a popular mod !
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I have done a similar conversion using a three spring centre and pressure plate. The centre has to be modified by fitting a shoulder for the first steel plate to bear against. I silver soldered an old steel plate to the centre and turned it to the correct diameter.
The three spring centre doesn't have a shoulder as the basket has a friction lining for the first plate to bear against.
A bloke I know has modified a basket from the later clutch by machining off the duplex sprocket and fitting a simplex one but he had to use a 44 tooth sprocket as he reckons to fit a 43 tooth type would weaken the basket.
I am still looking into this.
Trev.
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Hi All,
There used to be A65 type centres available to fit the A10 box, I dont know if they still are??
this meant that you could fit the A65 thrust washer behind the A10 chain wheel, then either an A65 centre or machine the lip off the four spring centre,
Then fit an extra friction plate into the basket first, this provides a much more solid base for the plates to press against, in the standard setup the inside steel plate is only supported on its inner edge and is able to flex away from the friction plate.
I know on some other motorcycles (including some BSA's) the rearmost plate is double thickness to try and prevent this happening.
The Pearson Suzuki clutch, see
http://archives.jampot.dk/Technical/Transmission/Suzuki_Clutch_conversion.pdf
Lovely clutch, lovely price! *eek*
*idea* *idea* Having read the article I went out and bought a couple of Suzuki clutches on ebay and am planning to do my own conversion,
I will document it and let you all know how it goes
I have my recently aquired RGS as a test bed, with its RR T2 box it will need a meaty clutch *ex* *ex*
Regards
John O R
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A bloke I know has modified a basket from the later clutch by machining off the duplex sprocket and fitting a simplex one but he had to use a 44 tooth sprocket as he reckons to fit a 43 tooth type would weaken the basket.
I am still looking into this.
Trev.
Interesting. I'm looking into doing this modification for my Silver Star, which uses the same clutch. I have come to the same conclusion on the basket...a 43-tooth sprocket would reside too close to the basket and the clutch baskets can't have much machined off them. Even a 44-tooth is going to be pretty close, but I think going bigger may introduce some clearance issues. My other thought was possibly using a B50 clutch...much more room around the outside for a 43-tooth sprocket...though it is quite a bit smaller. Just thinking out loud here...