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1Back to top Go down   Rear suspension spring compressor. Empty Rear suspension spring compressor. on Sat Feb 08, 2014 6:33 pm

sidecar paul

sidecar paul
Life time member
Life time member
I use a Spax rear unit, with adjustable damping, on my outfit and when the first one, bought in '88, deteriorated, I bought a new one in '98. As they are re-buildable I use one and keep a refurbed one ready to swop over as required (or when I fancy trying a different spring or something).

My old spring compressors are adapted car spring clamps and always damage the paint as well as being a bit awkward to use, so I decided to design and make something more elaborate.

My design parameters were:-
A rubber faced plate to contact the spring, to avoid paint damage.
A single screw to apply the pressure.

This is what I eventually came up with:-
The top plate had to be twisted into a helix to follow the spring contour.


Rear suspension spring compressor. Sam_0810

The damper shown here is the original 1988 one, which I have shortened, fitted a BMW bottom fitting to the top and re-made the damper adjustment in stainless steel. Although, once set where you want it, further adjustment of the damping isn't necessary, I didn't like the rusted up adjuster.


The gaiter, BSA Bantam, fits inside the spring and keeps all the muck and grit off the damper rod.

This next pic shows the tool in action, compressing the spring on an old clapped out BMW unit.

Note the rubber facing on the top plate......old inner tubes do have their uses.


Rear suspension spring compressor. Sam_0811

When contemplating on how to locate the main screw in the alloy block, I settled on using
 a K injector 'O' ring in a groove on the shaft!.......Works a treat.


Rear suspension spring compressor. Sam_0727

I don't suppose many of you will be rushing out to make on of these, but I thought I'd share the
design anyway.

Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

2Back to top Go down   Rear suspension spring compressor. Empty Re: Rear suspension spring compressor. on Sat Feb 08, 2014 7:50 pm

japuentes

japuentes
Life time member
Life time member
I have the original shock stored for future repair, so your design will serve me, thanks
Best regards
JAP


__________________________________________________
Rear suspension spring compressor. 2854237993 1988 K100RS SE/ABS
    

3Back to top Go down   Rear suspension spring compressor. Empty Re: Rear suspension spring compressor. on Sat Feb 08, 2014 8:37 pm

Oldgoat

Oldgoat
Life time member
Life time member
Great work Paul!   Cool What do you figure it cost you in time and supplies?

OG

    

4Back to top Go down   Rear suspension spring compressor. Empty Re: Rear suspension spring compressor. on Sun Feb 09, 2014 3:05 pm

sidecar paul

sidecar paul
Life time member
Life time member
Thanks JAP & OG,

Supplies were just from my stock of metal, but I did need some extra 8mm stainless which cost me £8. I'm fortunate to have a friend who lives about 150 metres away from me who runs Mallard Metals, supplying restorers and model engineers etc: very useful!

As we all know, time spent working on our bikes and projects for ourselves doesn't get counted, but I spent most of last week playing with that spring compressor.......most of the time pondering on how to make it.

It's always nice making swarf. Rear suspension spring compressor. 723598 

Paul.


__________________________________________________
'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015) 
....No CARS never ever!
    

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