The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: gpo746 on 27.02. 2018 21:33
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Pic 1 .This is my Swing arm from (I assume !) my 1954 A7 SS .
Pic 2 I just bought these bushes from Southern Division (via eBay) and looking at the measurements there seems to be a 0.75mm difference. Seems to be abit much of a difference.
These bushes are Part No. 42-4115 , (they are the smaller diameter ones) .
Pic 3 Swing arm inside diameter (with wifey being the hand model..I don't have nails that long !)
I realise these bushes have to be pressed in with so many tons of pressure. However with 0.75mm difference I would be worried someting would jam , split or go crack crunch *eek*... I would appreciate your thoughts guys .
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I'd send them back, some years ago I bought a set from a well known BSA dealer and they were just to thick I pressed one in a little and it was obvious it was wrong, apparently you had to put them in a lathe and turn them down a bit (not mentioned at all), not having a lathe I bit the bullet and bought another set from C&D autos (fitted perfectly).
Also wondered about putting them in a lathe when there is rubber in there, would it not squeeze up ??
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I had to turn my new set down too.
They are made incorrectly, and can be corrected as Bill says with a lathe.
Lee
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....apparently you had to put them in a lathe and turn them down a bit (not mentioned at all),.....
Maybe I'm being eccentric, but I suggest there'd be no guarantee that the outer sleeve be concentric with the inner, and any bit eccentric would magnify with speed *dunno*
Do you have the old bushes for comparison ?
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Sadly, no..I got the bike in a pile of parts and the swingarm was naked without the bushes , this is the first time I have seen the bushes in the flesh ..what is wrong with the manufacturers? *conf* Why can they not make things that ACTUALLY fit....!
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My guess is they are made for a different application or motorcycle and are readily available and cheap.
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I'd send them back, some years ago I bought a set from a well known BSA dealer and they were just to thick I pressed one in a little and it was obvious it was wrong, apparently you had to put them in a lathe and turn them down a bit (not mentioned at all), not having a lathe I bit the bullet and bought another set from C&D autos (fitted perfectly).
Also wondered about putting them in a lathe when there is rubber in there, would it not squeeze up ??
Hi Bill,
A bit costly to send them back as these people are in Germany . The thickness of the outside tube wall is a shade over 2mm . I am worried that shaving them down will only leave 1.25mm of meat of wall thickness. I am curious to know what the factory BSA or C and D autos repros wall thickness is? . It may seem silly but , I am concerned that the walls will either collapse or ripple under pressure of fitting them. .. am I right to worry?
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This thread has some info from my experience with silent blocs aka bushes, and some pics I found 010 interference fit was ok when it came to pressing them in without a large press etc
https://www.a7a10.net/forum/index.php?topic=4293.msg31755#msg31755
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Yep, the set I bought were too big, so skimmed them in the lathe. I machined them till they felt like they would just about go in by hand. But given the length of the bushes they were tight by the time I pressed the last of them in. This is typical of pattern parts *eek* and some original parts also need to be custom fitted too. I believe that's called 'fettled' in the UK, LOL
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Why can they not make things that ACTUALLY fit....!
Well they do (often) but nothing to stop dealers buying bushes made for 1 application and selling them for something else (like BSA swinging arms)
Agree with Dutch that turning on a lathe may bring about some eccentricity (helped by the rubber bit), but would think once pressed in it might not matter too much.
Welcome to the wonderful world of after market parts Dom
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Why can they not make things that ACTUALLY fit....!
Well they do (often) but nothing to stop dealers buying bushes made for 1 application and selling them for something else (like BSA swinging arms)
Agree with Dutch that turning on a lathe may bring about some eccentricity (helped by the rubber bit), but would think once pressed in it might not matter too much.
Welcome to the wonderful world of after market parts Dom
Hello Bill, I am no stranger to aftermarket parts believe me ! *lol* ..It has just been nearly a decade since I last laid my hands on a Brit bike . Took your advice and contacted C&D autos but sadly NONE IN STOCK !and looks that way for the foreseeable future. So, I am stuffed and looks like I will have to machine the ones I have down.
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This thread has some info from my experience with silent blocs aka bushes, and some pics I found 010 interference fit was ok when it came to pressing them in without a large press etc
https://www.a7a10.net/forum/index.php?topic=4293.msg31755#msg31755
Good Rig you have there ! exactly how I would do it ! Thanks that has confirmed that you should not need a mega ton press to shove them in . I will re-read your thread when it comes to getting mine done . Shame C&D have not got any bushes as I would have bought a set from them .
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Been thinking... *conf*
Weighing up the pros and cons I think I will return these as they are sub-standard . They are slack on the swing arm shaft to a point where I can "rattle " them side to side on the shaft. They are badly reamed out, not smooth , looks like someone has jiggled a small drillbit inside to get somewhere near the size as they are badly scored inside all over the place . Even If I turned the OD down to fit the swing arm the ID for the shaft will be no good, I will end up with a rickety swing arm . *eek*
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Has anyone tried fitting bearings in the swing arm? Would need internal spacer(s). Does the rubber serve a purpose or was it a cheapskate idea?
What are the required sizes: OD 32mm? Internal?
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Does the rubber serve a purpose or was it a cheapskate idea?
I read, heard , or was told the S/A should be tightened up somewhere about the riding position, the rubber then provided some damping/ resistance to the movement, whether that is the case I have no idea but I have yet to see a bush where the rubber has torn away from the rest of the bush.
Could be the S/A moves within the frame (inner sleeve not tightened enough) I don't know it is a funny set up
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Didn't the Greeves front end do something similar?
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Hi All,
I read, heard , or was told the S/A should be tightened up somewhere about the riding position, the rubber then provided some damping/ resistance to the movement,
That is the correct way to do it,
Rubber in torsion bushes are used in many auto applications
John
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These bushes are a complete b*****d *angry* *problem* *work* *rant* I took mine to be removed by an engineer mate who's been restoring classics for years. After pulling some faces, three hours (£75), an acetylene torch and burnt hands, we finally got them out. Taking the s/a off was enough of a hassle as the spindle refused to budge, we had to destroy the rubber in the bushes then cut the spindle to release the s/a. When the s/a was off, it was a case of trying to remove the outer metal shell of the bush from inside the s/a, which is almost impossible when removing the first one as you can't even bash it out from the other side. Had to mangle the thing from one end and keep cutting/bashing until it gave up. *razz* *work* *pull hair out*
Then, on refitting, they pressed in ok but the spindle wouldn't fit. The bushes had to be reamed out until the spindle would actually go through. When I got to fitting the s/a to the frame, I discovered that the s/a eyes/lugs had been bent slightly and the spindle wouldn't go through. Lost my temper and got a big hammer only to almost ruin my new spindle. All this took me about a week (just to get the s/a sorted). *doubt* *bash* *pull hair out* *sad* *angry* *problem* *razz* *evil*
I think my mate saw the fury but pointed out that, now fitted, the bushes would probably outlast me - one to leave for posterity. *eek*
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Been thinking... *conf*
Weighing up the pros and cons I think I will return these as they are sub-standard . They are slack on the swing arm shaft to a point where I can "rattle " them side to side on the shaft. They are badly reamed out, not smooth , looks like someone has jiggled a small drillbit inside to get somewhere near the size as they are badly scored inside all over the place . Even If I turned the OD down to fit the swing arm the ID for the shaft will be no good, I will end up with a rickety swing arm . *eek*
That’s a bugger, C&D Must have sold the last of its “good” batch then. The problem is most retail suppliers get their parts from the same manufacturer, so when one has it duff stock, they all have. The nz supplier, britishspares.com had all its stock of bushes turned down in size a few years ago after I returned some with the complaint they were over size (I saw them in the machine shop being modified) but I don’t know if they still have some left.
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Has anyone tried fitting bearings in the swing arm? Would need internal spacer(s). .............
Motto Gutzzis have tapered roller bearings- fully adjustable.... *wink2*
If machining them down I'd also expect that they'd be best done in pairs on a common spindle ?
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Similarly to the Guzzis, my 1959 BMW R60/1 had taper rollers on the swing arm and the Earls forks if I remember correctly.
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I read, heard , or was told the S/A should be tightened up somewhere about the riding position, the rubber then provided some damping/ resistance to the movement...
That could just be so the rubber is in as little preloaded torsion as possible to avoid early failure. I seem to remember in my young days when fitting rubber bushes to motor car suspensions that the vehicle had to have the suspension in normal position, (weight of car on) before tightening the nut, for the same reason.
The swinging arm A has hydraulically damped movement. How much effect would that rubber bush have?
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There is a useful step-by-step guide to removing and fitting swinging arm bushes on the Cheshire BSA website.
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The swinging arm A has hydraulically damped movement. How much effect would that rubber bush have?
Yes I wondered that but OTOH have you tried twisting a bush or lifting the S/A once it's installed correctly but not connected to the suspension dampers, I'm in two minds on this one.
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There is a useful step-by-step guide to removing and fitting swinging arm bushes on the Cheshire BSA website.
Hello beezermacc , Maybe I'm thick *doh* but I have just been on their website and I can't find it? do you have a link I could use please.
Thanks
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..Yes I wondered that but OTOH have you tried twisting a bush or lifting the S/A once it's installed correctly but not connected to the suspension dampers, I'm in two minds on this one.
To be honest Bill, yes I did when I had my RR late '70's, figured I should grease the 'bushes' but hit a road/silent-bloc *pull hair out*...gave up and *beer*- cheaper and easier.... I think in the end, I settled on; slack off the spindle and let it sit with machine weight (and maybe a bit)...kinda like G-B's idea, but that was long ago
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Has anyone tried fitting bearings in the swing arm? Would need internal spacer(s). Does the rubber serve a purpose or was it a cheapskate idea?
What are the required sizes: OD 32mm? Internal?
Replaced mine with bronze bushes. Rocksteady on the road. Wouldn't want anything else anymore
https://www.a7a10.net/forum/index.php?topic=11767.0
At the bottom there's a reply from edboy regarding needle bearings
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The bushes had to be reamed out until the spindle would actually go through.
Proof right there that they weren't the "correct" bushes as used by BSA. Silentbloc bushes, by their construction, would never need reaming before use, so some supplier has been buying in "near enough is good enough" industrial components.
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Probably right Rex, and those were from C&D so thought I'd be ok. Similar thing happened with the lower fork bushes which simply wouldn't fit. Had to keep taking thous off the inside of the lower fork until they fitted (very tight). First time out I braked and the forks jammed in the depressed position - had to give the 'bars a sharp pull to release.
This was the first Brit bike I'd owned and restored (apart from a short fling with a B31). I've subsequently learned that restos using 'pattern' parts is certainly not an exact science, and innovative adaptations are a must. When I'm out on the road and the bike's purring along, all that swearing is quickly forgotten. Now to stop oil p*****g out of the primary chain case!! *cry*
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these non fitting parts have been here for decades, any brit bike owner needs a lathe or and a miller or a mate who has them.an experience [ one of hundreds ] i had in the 80s was a gearbox sprocket from CD autos that was oval and made the chain 2inch slack then super tight. because said sprocket was brand new i was thinking bent mainshaft/ chain/ back drum oval etc. but once the new gearbox sprocket was set up in the lathe it was found to be all over the place. CD wouldnt swap it . problem solved with a good second hand one from autojumble. and dont get me started on the number of parts with crap threads that need nurseing for hours to get them to do there job
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Been onto the supplier (Southern Division) in Germany. I supplied him with the same photos I put on here and within 24hrs he got back to me after he measured the ones he had in stock . The ones he had supplied me were from MCA and they all measured the same as mine. He reckons there are only TWO wholesale suppliers that sell these items - WASSELL and MCA , WASSELL have no stock and have not had any for some time . It would appear the ones we are seeing now are from MCA. They can be identified by the grainy OD and shiny zinc coating . (I believe the original BSA articles were smooth matt in apperance) .The vendor in Germany thanked me for raising the issue and offered me a 50% refund If I wanted to keep the bushes and turn them down. Given there is an apparent shortage of these items I decided that I would take a chance . The seller was true to his word and has issued me the 50% refund as promised.
To be fair - I can't fault him on service!
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Been onto the supplier (Southern Division) in Germany. I supplied him with the same photos I put on here and within 24hrs he got back to me after he measured the ones he had in stock . The ones he had supplied me were from MCA and they all measured the same as mine. He reckons there are only TWO wholesale suppliers that sell these items - WASSELL and MCA , WASSELL have no stock and have not had any for some time . It would appear the ones we are seeing now are from MCA. They can be identified by the grainy OD and shiny zinc coating . (I believe the original BSA articles were smooth matt in apperance) .The vendor in Germany thanked me for raising the issue and offered me a 50% refund If I wanted to keep the bushes and turn them down. Given there is an apparent shortage of these items I decided that I would take a chance . The seller was true to his word and has issued me the 50% refund as promised.
To be fair - I can't fault him on service!
In the circumstances that’s a fair result, a word of caution, when I saw some blocs being machined down the machinest guy was complaining that they weren’t round, being made of cheap thin wall tube, which made the job take much longer, I’m not 100 % sure how he got around the problem, but he was using a 4 jaw chuck and dial guage to set them in the lathe, from memory.
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Agreed berger. If I had the space, money and know-how I'd make as much as I could myself. Unfortunately, I don't have any of these things so I'll have to take my chances and consult my engineer mate. At the end of the day, the bikes are all about riding so, whatever it takes, get the bloody beasts on the road!! *smile* *beer* *yeah*
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There is a useful step-by-step guide to removing and fitting swinging arm bushes on the Cheshire BSA website.
Hello beezermacc , Maybe I'm thick
*doh* but I have just been on their
website and I can't find it? do you have a link I could use please.
Thanks
Gpo746
Here is the link. Looks like a good wright up by beezamac
https://tinyurl.com/ydagtljb
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yes wortluck if my dad hadnt have been an engineer i would be on those foreign bikes, ime lucky now that older brother has a heated workshop fully stocked and knows his stuff, i will admit i spent too much time in the pub instead of standing over dads shoulder, but it still pisses me off when basically nothing is made correct, ps whenever i see a 4 jaw mentioned i know people know their stuff.
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Too right. I'm more of a rider than an engineer, and I'd rather be riding than cocking stuff up in my garage and wasting time not being on the road. I'm pretty competent with a lot of stuff, but specialist/critical things I'd rather leave to those in the know. Good example is my family estate in for a timing belt. Could probably do it if I had the time and didn't need the car, but neither of those options are available to me so it's £370 at a local indy! *eek*
Just so you know, I'm not on the bike today ;)
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There is a useful step-by-step guide to removing and fitting swinging arm bushes on the Cheshire BSA website.
Hello beezermacc , Maybe I'm thick
*doh* but I have just been on their
website and I can't find it? do you have a link I could use please.
Thanks
Gpo746
Here is the link. Looks like a good wright up by beezamac
https://tinyurl.com/ydagtljb
Looks like its in Microsoft Office..which I cannot open *problem* !. Only found this out after an hour of faffing about with Adobe and cursing at the computer *rant* ...wifey (10 years my junior) found this out fairly quickly. *respect*
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Here is the link. Looks like a good wright up by beezamac
https://tinyurl.com/ydagtljb (https://tinyurl.com/ydagtljb)
Looks like its in Microsoft Office..which I cannot open *problem* !. Only found this out after an hour of faffing about with Adobe and cursing at the computer *rant* ...wifey (10 years my junior) found this out fairly quickly. *respect*
I don't have MS Office installed on this PC. I have the Open Office Suite, (which is free) and that will open the document.
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Here is the link. Looks like a good wright up by beezamac
https://tinyurl.com/ydagtljb (https://tinyurl.com/ydagtljb)
Looks like its in Microsoft Office..which I cannot open *problem* !. Only found this out after an hour of faffing about with Adobe and cursing at the computer *rant* ...wifey (10 years my junior) found this out fairly quickly. *respect*
I don't have MS Office installed on this PC. I have the Open Office Suite, (which is free) and that will open the document.
Brilliant ! That does it nicely thanks *smile* I'm Not 100% with computers ...
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when i did my s/wing arm bushes i gave up and took 'em to our local RE dealer bikeshop, they have avery sturdy press ,I talking to the owner and we heard the loudest bang I've heard in a long time ,the owner went white rushed into the back expecting to see body parts instead the litlle apprentice came back in with a grin from ear to ear ,he just said "that got it " turned out he'd had to wind it up to max and nothing moved ,he turned his back and everything let fly but it worked ,don't exactly look forward to have to renew 'em again *countdown* *whistle*
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when i did my s/wing arm bushes i gave up and took 'em to our local RE dealer bikeshop, they have avery sturdy press ,I talking to the owner and we heard the loudest bang I've heard in a long time ,the owner went white rushed into the back expecting to see body parts instead the litlle apprentice came back in with a grin from ear to ear ,he just said "that got it " turned out he'd had to wind it up to max and nothing moved ,he turned his back and everything let fly but it worked ,don't exactly look forward to have to renew 'em again *countdown* *whistle*
Blimey! ...it does sound like a daunting job . I will have a go and let you all know how it goes .
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Thinking back to my first experience of fitting these bushes ,that would be 1968, I fitted the bushes to the swingarm of my A7SS using two blocks wood with a studded bar right through the swingarm ,large washers etc no problems , so the guy who questioned modern sizes/quality was completely correct .