Fork Slider Extensions

lcrken said:

jseng1 said:

Yes they are too short and there is binding.

I made extensions when I was racing. I threaded the OD of the original sliders and made screw on caps that raised the bushing and the seal about an inch or so. The bushing was non metalic and they worked wonderfully. But its a big PIA to do and still avoid leaks.

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Jim is being too modest here. Not only did he make the slider extensions and cool bushings, but while he was at it he also made his own tubes out of thinner wall 4130 and devised his own cartridge dampers using the modern style shim stack internals from rear shocks, Fox Shocks, I think. I rode the bike with them after I bought it from him, and they really worked well. I eventually took them off and fitted larger diameter Forcella Italia forks to get the adjustable damping, as well as wider spacing for the twin disk front mag wheel with racing slick. Jim's forks actually had better damping, but I wanted the larger diameter tubes of the Forcella Italia/Ceriani forks.

And this was all 25 years or so ago.

Ken

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The dampening units on my old custom forks came from Marzochi rear shocks. Someone please market the extensions so I don't have to. Together with the JS turkite bushings and alum sleeves - the Nort forks would work really well. I would like to see about an inch or so more extension.

Sorry, I've been absent.

Thanks Fred and Jim for validating my musings.

I have a set of Greg Faust's extended damper rods in my '73 750 and the kit enabled additional travel that picks the front end of the bike up.
My head pipes appreciate the greater ground clearance and the topping clank is gone.
Previously I extended the shocks to get that clearance but that made the bike steer too quick.
While I do not notice any increase in "stiction" with the Faust kit, I do not like the idea of it's lost slider/stanchion engagement.

Anyway, I like to keep it stock'ish, so improved but stock, so . . . . if anyone is going to make any extensions, I'm interested.

Madass?

To get back down to original sag height just put in a rather weaker spring than the long one, it will still retain the silent stops. There is no need to worry about injury to 2" extra close bushes, less parts over lap, heck can't even stay full extended on bike sag alone, then add rider and some motion energy to see its essentially impossible to load forks much until compressed into normal sense of over lap back up. Only 3 ways to injure at full extension, a wheelie into oncoming grill, accelerating up slope so front unloaded and strike a shelf or a hole wheel hooks into or a hi side that lands bike mostly side ways on full extended full on turn stop forks. Even then only thing injured are bent stanchions &/or yorks which over lap support offers nil protection. Swooheroo Dave bent his almost fully compressed forks braking too short into a bumper not very fast. If ya want stronger Roadholder forks for some reason then look for special strength stanchions and yokes but then the stem and spine may give first.

Making extensions to the standard sliders would have to have the new top bush concentric with the old stock top bushing, so that the stanchions could slid properly.
I assume this would involve a lot of setting up properly in a lathe to get the boring correct in the new extension for the top bush to line up correctly.
With the new top bushing higher up in the slider, the top out damping (that's a laugh on a Norton) would now be even more none existent.
The top bush wouldn't cover the damper hole in the stanchion any more. This could also be repositioned I assume.
A lot more work than just a simple slider extension!

It's not two inches more like 1 1/2. And a big part of how the kit works is how the oil stops are fixed by letting the sliders travel the full six. I like the extensions shown here but it may require putting some worms back in the can. I would try to make them with very good concentricity and try them on several machines before looking for problems.