seeking Rear suspension spring for Sq 4 MK II Plunger frame

[pauldridge]

I posted here previously regarding the low ride height of my '53, with photos of the plunger, and the general consensus was that my springs were tired, replacement with new ones recommended.

At the time I placed an order on D'fly, their website showed "plenty in stock". However, after waiting impatiently the customary 3 weeks for delivery of my package to the US, I was dismayed to find only ONE spring in the package, the remaining one marked "back order". Inquiry to Draganfly revealed that new stock is on order, but with a MINIMUM of 10 weeks availability!

Of course,one spring isn't going to do me a bit of good, yet I'm anxious to correct this, since I keep scraping my new silencers during the most timid corner lean.

Just wondering if anyone knows of another source for these springs? The one I received is 6.75 inches long (although the D-fly catalog specifies a shade under 6.5 inches) and the spring is 2 inches in diameter. (or perhaps springs for another marque might be adaptable?)

Any help would be appreciated.

[KevinOToole]

I wonder if the coil springs could be replaced with disc springs (Belleville washers). Standard washers could be used and stacked in different configurations to give the correct travel and load. I'm no expert on these types of spring, so we could do with some input from someone (an engineer) with knowledge of disc springs. There is a video on YouTube that shows how they are used. https://www.youtube.com/watch?v=QhODuFC3BFc
Alternatively, you could just pre-load the original springs until another spring is available

[pauldridge]

Thanks Kevin,
I did remove and examine an existing spring on my bike, and found that they are fully 1/2" shorter than the new spring from D'fly. I have decided in the interim to turn a 1/2" thick by 2" diameter aluminum spacer disk to install at the top of my old springs to bring ride height up (plus it should increase spring resistance as well)

[paul.jameson]

Phil,

There must be someone who makes springs in your area but if all else fails, email me full details of the spring which means wire diameter, number of coils (exactly, so 16 - 3/4 rather than 17) spring diameter, spring length and finish of the ends. Photos can help in this. My spring maker will usually knock them out in 2 or 3 weeks but in an emergency you can have it tomorrow - at a suitably inflated price.

[pauldridge]

Thanks Paul
I'll get back to you
Phil

[pauldridge]

As an interim measure, I cut a 1/2" spacer (the difference in length between old and new springs) from 2" aluminum rod. Then it got installed on top of the old spring.

The 2" diameter of the spacer rod was ever so larger than the inside of the chrome plunger cap. My lathe belt broke, so I had to reduce the diameter on a belt sander, but I did get it done, and the ride height has improved considerably, along with a slightly stiffer (and more desirable) ride.

I made up a crude but effective tool for compressing the inner spring. I milled an indentation into the bottom "foot" to keep it located over the lower nut securing the internat shaft. I then wrapped the edge of the upper circular "arm" with several layers of duct tape to protect the chrome surface of the top cap. The diameter of the upper tube gave ample room to replace the dome nut and washer. It worked like a charm: