Author Topic: swingarm bush strip- piece of cake!  (Read 1249 times)

Offline 1660bob

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swingarm bush strip- piece of cake!
« on: 27.09. 2009 09:26 »
Er, NOT!
Just spent all of yesterday stripping out the swingarm from the frame and removing the silentbloc bushes.Are they called silentbloc because BSA refused to comment on them? *smile*
This really is a P.I.T.A. of a job.Spindle hoplessly seized in so I started by strapping short lengths of angle iron to the frame around the pivot hole to protect the tubes as i got to work with a 4 1/2" grinder. I ground away the weld attaching the small elliptical plate to the spindle on the  brake pedal side and removed the plate from the spindle. This revealed that the frame pivot hole was just as knackered on this side as the other *sad2* I did not want to saw through the ends of the spindle via the narrow gap between frame plates/swingarm bush housing as it risked  damage to the ends of the swingarm, so i placed the elliptical plate over the other (threaded)spindle end (to protect the frame) and ground away that spindle end flush with the (elliptical) plate.This gave better access for me to grind away the spindle form inside using an electric drill and the corner of a cylindrical hss grinding bit at 45 degrees.Again the elliptical plate I used as a sacrificial protector for the frame.With a bit of careful grinding I cut through the spindle ends from inside and freed the s/arm with no damage .Frame spindle holes are well worn oval.What a dreadfully poor design-the frame plates should be twice as thick there, or re-inforced with a bush at least,any way, looks like a weld up job later.
I used a 38mmdeep 29mm dia holesaw (screwfix)to cut the rubber bushes through-bit tight on the inner steel bush-a 30mm cutter poss. better but I cut until it bottomed out leaving just a small amount of rubber in each bush which I was able to tear out having welded a "handle" onto the end of the spindle.That got the spindle out, now for the bush outers still in the swingarm.I tack welded a length of flat steel strip edgeways to the inside of the bush, being careful not to burn through the bush and weld it in! and used it to collapse one side of the bush inwards enough for me to start bashing through its length with a brass bar cut to a sharp angle at the end as a sort of soft chisel,avoiding any damage to the swingarm bores.Very difficult job but eventually got them out OK,no damage.
Simple! Now all I have to do is get new bushes and fit them-I have heard that the s/arm may have to be reamed out/Are replacement bushes bigger? Any info appreciated, Regards Bob.

Offline A10Boy

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Re: swingarm bush strip- piece of cake!
« Reply #1 on: 27.09. 2009 09:54 »
Blimey, sounds like a right pain. Well done and thanks for telling us about it.
I'll leave it to others to offer any help they can on the refit.


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Online RichardL

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Re: swingarm bush strip- piece of cake!
« Reply #2 on: 27.09. 2009 12:47 »

Yes, some new bushes are, apparently and painfully, a bit oversized. Here is a link to four pages of discussion on the subject. My own nightmare of removal and replacement is described there. Also, the whole concept of operation, which I did not really understand in the beginning, is descibed.

Richard L.
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Offline MikeN

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Re: swingarm bush strip- piece of cake!
« Reply #3 on: 27.09. 2009 20:39 »

Any info appreciated, Regards Bob.

Remember that if you have an early G/Flash or RGS (or RGS rep) fitted with a rod operated "crinkle" hub you will require to purchase the bushes with a smaller bore through the middle than if you have the other type with the cross over shaft  (which has a larger dia. pivot pin).
  It sounds like, after you have welded up the worn holes , you will need some carefull marking out before re-drilling to ensure correct alignment of the swinging arm (and therefore, wheels).
 Tricky without getting the whole chassis up on a marking-out table.
Good luck,Mike
Good luck