New Product - Turcite Fork Bushings

Gottem in NZ back 80s , put a 68 A65 together with em . Same dia. stauchions as Norton . Seemed ok for a BSA .
Wouldnt want pitted rusty stauchions , but theyd still work . Some thoughts on Oil compatability . Think we used
ATF & STP . These were a few thou clearance , 5 ? , Could get a minor chatter provoked, leant over on a ripple or
tar joins at 60 / 80 , but staunchions wernt perfect . Id imagine the seal woul improve the hydraulic action at 1 1/2
thou or so clearance , and slide smooth on clean stauchions . Though were got as ' cusion ' for the original staunchions
machined to fit , alledgedly .

Would assemble lubed . Like Most Things .

Brooking 850 said:

Any feed back from guys using thesefront fork bushes from JS ?

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Plastic bush's are fine, but, theres always a But, To maintain a correct clearance the stanchions and slider dimensions have to be right.
I have made a few Oilon bush's , in the workshop they fit OK ,customer gets them and they are to tight. :!:
The plastic deforms easy ,so any undersize slider top bore will compress them. and slightly oversize stanchions make it worst
I guess the slit is designed to allow some contraction issues, once fitted correctly they are great, and will last years.

Hi John

Any news on the springs you were making up? Are you going to be making these bushes as well?
See you next season? No Darley but Donnington & Silverstone are the big ones.

Happy New Year

all the best Chris
in the garage as we speak

Chris said:

Hi John

Any news on the springs you were making up? Are you going to be making these bushes as well?
See you next season? No Darley but Donnington & Silverstone are the big ones.

Happy New Year

all the best Chris
in the garage as we speak

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Hi Chris, Made some composite springs kits up with nylon connectors for a scott, there is no buckleing or side rubbing, Nylon bush's tricky little things to get spot on...i like to have the sliders and stanchions on the bench..made up some for EEK racing Adrian Debman,he is pleased.
Hope to see you in action this season.

jeffdavison said:

Jim,

Fork tube diameter is 1.3585"
With the slit, the bushing expands and if the wall of the bushing were "just" a bit thinner it would have fit with no problem. As it is the Turcite part is an interference fit ...
JD

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The first few bushings were dimensioned for an average fork tube of approx 1.357 to 1.358 diameter. In the real world this turns out to be too tight for tubes over 1.358" So now all turcite bushings are dimensioned for 1.359" tubes. I had to exchange a few bushings. The fork tubes being various diameters makes it difficult to make an exact product that works for everyone - hence the adjustment. The tubes can vary from 1.356" to 1.359" (bushing inside diameter). The slit in the upper bush allows for expansion/contraction with extreme temperature changes. This isn't a problem with the smaller diameter lower bush - in part because the alum fork legs are more accurately dimensioned at 1.5" (bushing outside diameter).

The fit seems to be good now for everyone.

John
Let us know how the springs with nylon connectors work out, less friction? How about a photo?

Picture on it's way[thanks to Lab]
will show the built up spring assembly, Image shows Scott damper assemble, but adapts to Commando.

John, I had the same thing, the spring buckling on my set up with 1 inch extra preload on progressive springs. I was wondering is another way to combat this, would be to make some internal nylon spacers on the damper rods and hold them a distance piece in the centre and some light springs at either end?

Cheers Richard

This spring set up is very complex in it's compression graph, firsty the top "reduced" springs compress,then the bottom 70mm length. then the centre 50mm ones!
Early tests on stock springs show a steady "snake bend" resistance,near the full compression is requires an extra 10KG above the natural resistance to fully compress the spring.
It;s surprising how much friction there is.. look how the spring sides wear, and think where all the grindings go :!: