Author Topic: Dragonfly rear wheel spacers  (Read 7339 times)

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Offline Les Mills

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Dragonfly rear wheel spacers
« on: 22 Nov 2011 at 16:41 »
The previous owner of my recently acquired Bike was a worse mechanic than me.  On a recent test run the speedo outer cable broke near the gearbox.  The reason being that on tightening the nut to hold the gearbox against the spindle the wheel locked up.  His remedy was to undo the nut and tighten it against the fork - hence the speedo cable was holding the gearbox in place with the aforementioned the result.  What a performance removing the wheel, on a Gold Star of the same era all that is needed is anything that will fit in a 3/8 dia hole to remove the spindle and the job is done in seconds.  With some help from the less than informative Workshop manual I worked out that a longer spacer was needed between the bearing nut and brakeplate.  This is where access to the works drawings would have saved a lot of trial and error.  Eventually I hit on a suitable size and thought my dilemma was solved.  Not so.  On tightening the brake anchor bolt the brakeplate twists and fouls the sprocket.   
                   There is no space for adjustment of the brake anchor,  there are no spacers   on the right hand, gearbox side so that the brake hub can be as far over as possible, the spacer on the near side has hardly any clearance .  It is as if the width of the swinging arm forks is too narrow, again a look at the works drawings would be handy.       

Will be grateful for any suggestions   
                                                              Regards,  Les         

Offline eddie

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Re: Dragonfly rear wheel spacers
« Reply #1 on: 22 Nov 2011 at 17:27 »
Les,
        The main problem with the Dragonfly is that several components were changed during it's short production run - the wheels were included in this. Early Dragonflies had the same hubs as the earlier Mk5 machines - later models (from mid '56) had British Hub wheels, but these were never shown in either the parts books or owners manual.
       I assume you have the later hubs - if so, lets assume your rear wheel is assembled correctly and the brake plate does not foul on the drum, fit just the locknut to the brakeplate and offer the wheel up to the swinging arm. With the brake anchor boss touching it's anchor plate, check the distance between the wheel spindle locknut and swinging arm - then fit a spacer of that width between the brakeplate and locknut. You should now be able to tighten that side of the wheel spindle without distorting the brake plate. Moving to the other side of the wheel, there should be a spacer between the bearing lock nut and the inside of the speedo drive, that keeps the speedo drive gear from bearing on the end of the hub. There should then be another locknut for the speedo drive, with maybe a washer to adjust the whole assembly to the same width as the swinging arm. The chain adjusters should then be fitted on the outside of the swinging arm.
     Don't hold on to any false hopes regarding the drawings - there are very few that refer to the later Dragonflies and definitely no assembly drawings for the wheels.

      Regards,
                   Eddie.

Offline Les Mills

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Re: Dragonfly rear wheel spacers
« Reply #2 on: 23 Nov 2011 at 10:27 »
Hello Eddie,
                          Thank you once again for your prompt reply.  Yes, I do have the later British Hub Company Brake.  I did as you suggested, and found that a 0.540" spacer would be needed.  this amount would push the hub over so far that there would not be room for the offside locknut never mind the speedo drive.  Also, it looks as though it would severely affect the wheel alignment.
                          Any ideas what to do next?  I'm really baffled

                                                   Kind regards,
                                                                              Les

Offline eddie

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Re: Dragonfly rear wheel spacers
« Reply #3 on: 23 Nov 2011 at 11:33 »
Les,
       Check that the swinging arm has not been 'squeezed'. The standard width is 7" between the legs.
          Regards,
                       Eddie.

Offline Les Mills

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Re: Dragonfly rear wheel spacers
« Reply #4 on: 24 Nov 2011 at 08:17 »
Eddie,
                 Fork width is 7 5/8" which I would say is good.  Hope you have some more ideas or perhaps our other 87 readers may have some suggestions.

                                          Regards,
                                                                 Les

Offline Les Mills

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A Big Thank You
« Reply #5 on: 25 Nov 2011 at 11:11 »
A very big thank you to Eddie for patiently solving my problem.  Hope all the readers enjoyed the saga.
                                         Regards,
                                                                   Les

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #6 on: 23 May 2012 at 12:20 »
Hi Eddie and all,
Hope you don't mind me asking about these posts.
My bike is new to me - Dragonfly with British etc rear hub.
The part of the reply difficult for me is the references to the locknuts either side, because I don't seem to have them.
I have a nut against the bearing on the offside (UK), and the end nuts outside of the swinging arm, both sides.
The wheel was assembled in the bike when bought, and appears to work, but with the brake binding.
A variety of home made spacers had been used.
Q1 Is the axle stepped so that only 1 bearing nut is needed?
Q2 Should there be 2 more lock nuts in the setup?
I note the swinging arm width 7-1/2" and the method of determining spacer lengths.
I've added an attachment - hope it works.
Any help appreciated -I don't want to ride this bike until I'm sure of the security of the rear wheel and bearings.
So thanks for any inf.
Dave

Offline eddie

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Re: Dragonfly rear wheel spacers
« Reply #7 on: 23 May 2012 at 14:18 »
Hi Dave,
           The diameter of the rear wheel spindle should be 5/8" on either end with the centre portion between the bearings about 1" dia. The 2 wheel bearings should be pressed up to these shoulders. Then, outboard of the bearings there is a 1/4" thick spacer with a felt seal around it, followed up by a thin facing washer (for the seal). From this point, working on the brakedrum side you have the lipped cover (with the depressed centre) followed up by a thicker spacer, the brake plate, another thick spacer and a locknut (almost a full nut). As this locknut pinches up the whole assembly on that side, the lipped cover has to be free to rotate on the hub. Moving over to the speedo drive side, the bearing, seal and facing washer is pinched up with a shouldered locknut (reduced diameter outwards). Next comes the speedo drive backed up with a washer, and retained by a thin locknut.
        If you thick you have the correct assembly, but the wheel still does not run free, I would suggest removing the speedo drive and the brake plate (but do the locknut up again) to ascertain whether the fault lies in the bearings rather than the brake plate or speedo drive. If the bearings are stiff but free up when one of the locknuts is slackened, then the bearings are carrying a preload (probably due to a bearing not having gone fully up to the shoulder in the hub). With the locknuts tightened, give each end of the spindle a tap with a copper-hide mallet to jar the bearings into place - the spindle should then turn more freely. If the problem isn't in the bearings, then refit the brakeplate and recheck - likewise with the speedo drive. Bear in mind that it may be necessary to add more shim washers should the brakeplate or speedo drive be bottoming out on the ends of the hub.  From memory, the spacers used by 'Mr Douglas' were about 1 1/8" diameter - spacers made from offcuts of tube are not man enough and will crush when the nuts are tightened.
       I have attached a copy of the assembly drawing for a British Hub rear wheel - hope it helps!

       Regards,
                  Eddie.



Larger view
« Last Edit: 24 May 2012 at 20:13 by Dave »

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #8 on: 23 May 2012 at 15:21 »
I've modified the message.
Eddie,
Very many thanks for the reply and the diagram.
Looks like I am missing 2 locknuts, and 2 proper spacers.
The nuts at the very end of each side on the diagram, presumably are the nuts to go outside of the swinging arm?
Do you know how I can check the dimensions for the missing locknuts and spacers against standard parts?
I can probably work out lengths, if unknown.

Anyway, the diagram is brilliant info.

Many thanks,
Dave
« Last Edit: 23 May 2012 at 17:04 by BrmBrm »

Offline eddie

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Re: Dragonfly rear wheel spacers
« Reply #9 on: 23 May 2012 at 17:06 »
Dave,
         If you are a member of the LDMCC, post war spares probably have them in stock. Also, the Club is updating the Dragonfly spares book to include details of the British Hub wheels.
      Regards,
                  Eddie.
       

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #10 on: 23 May 2012 at 17:13 »
Brill. thanks again Eddie, I'll try the spares emporium.
Dave

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #11 on: 03 Jul 2012 at 09:51 »
Hi Eddie and Les Mills,
Thanks for previous help on spacers for Dragonfly wheel with British Hub.
I've taken on board everything and managed to progress somewhat.
I've noticed that the brake torque arm screw is a shouldered screw
I've removed the speedo drive, and stripped, freed off, re-assembled and re-fitted.
So, using packs of M16 and 5/8" washers of varying thickness, I've replaced the thin-wall steel tube previousley used by someone.
   Firstly I set the set of washers inside the British Hub brake drum to give me 2 to 3 mm clearance from the edge of the Al. cover to the drum after trueing this edge. (The inside bearing cover turned freely on the  bearing boss). Fitted a nut and washer to secure the brake backplate to the spindle.
   Fitted the wheel, and secured the torque arm shoulder screw without any washers. Measured the above nut to frame gap with the shoulder screw at a mid clearance position and fitted washers . Secured a nut and washer outboard of the swinging arm.
   Checked that all spins freely.

NOW THE OTHER SIDE
With the Speedo drive fitted I've only got about 3mm to fit a thin nut and spacer, and the inside swinging arm measures 7-5/8".
So my question is - Have I got the same problem as Les Mills?
Any ideas most welcome.

Thanks,
Dave

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #12 on: 23 Nov 2012 at 17:22 »
Spacers now sorted, at least until re-check and re-fit the wheel.
Solution for my manky, bodged, messed about with and otherwise sub-standard set-up was as follows :-
  Obtain 5 nuts and select 2 of them
  Reduce one to 1/4" THK for the speedo drive side.
  Discard all previous home-made thin tubular spacers and washers.
  Obtain loads of 5/8" & M16 washers of varying thicknesses but still can't fit the wheel correctly.
  Post 3 different requests for help on the forum
  Had help from 3 members of the forum in 6 months. Wow!
  Detect that the torque arm bolt is a shoulder screw and must not be fitted with washers.
  Realise that the piece of Al saucepan that covers the steel brake back-plate is incorrectly formed.
  Re-form so that the brake is set further into the drum, with spacer washers reduced.

Now the wheel can be fitted centrally in the swinging arm.
The shoulder screw fits correctly with clearance equalised.
The brake is not now distorted.
The wheel turns.
The sprockets line up - well at least as good as they ever will given the gearbox spring shock absorber.

BSA I forgive you for all your sins, and realise why you lasted so long in the dying days of the British motorcycle industry.

Offline eddie

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Re: Dragonfly rear wheel spacers
« Reply #13 on: 23 Nov 2012 at 17:52 »
Dave,
         Dont blame 'Douglas' for a previous owners amateur attempts at maintenance - the original setup was more than adequate. Also, look again at the shock absorber and you will find that the chain alignment is unaffected by the action of the shock absorber.

    Eddie.

Offline BrmBrm

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Re: Dragonfly rear wheel spacers
« Reply #14 on: 23 Nov 2012 at 18:38 »
Yes, I suppose you're right Eddie - and thanks for your help in the past!
Thank heavens that the shock absorber doesn't work as I thought it might, I was premature in thinking this, not having got that far yet. I suppose I won't find out how good these  bikes are until it eventualy gets on the road.
Best wishes,
Dave