Fork Slider Extensions

Seems to me that our forks' sliders are too short, that there is too little distance between the bushings.

So, just wondering, has anyone made, or attempted to make, screw in extensions that would provide more distance between the bushings and move the seals up by the same amount.

What would you hope to achieve by doing that then John?

Dave.

I have often thought the same thing, & my suspicions were confirmed when I took a pair of forks to Maxton Engineering for mods. Ron Williams told me the reason for this . Roadholders & most other British forks were designed to use external springs. If the sliders had been made longer there wouldn't have been enough spring room. Longer sliders would make the forks more rigid & less prone to stiction. (as indeed would modern bushes)
Martyn.

Ask madass to cast and machine you up a longer than standard set of sliders. ?
Shouldn't cost more than an arm and a leg !
Don't know what measureable benefit you will see though.

Matchless/AMC used those phenolic bushes, were supposed to reduce stiction.
And were renowned for their smooth action.
These days, folks rip them out and fit bronze bushes.
Nought as queer as folk ??

If you are hell bent on improving your roadholders, bigger diam fork tubes should be on the menu too.
And make em upside-downies while we are at it too,
with adjustable damping and rebound ?

Heck a whole inverted frontend can be had these days for less than $250.

And are easy to make fit. But then you end up changing wheels, brakes, handlebars........ Oops here comes the rabbit hole.

There's built in 6" travel if the damper rod lengthen ~ 2.5", then forks built in top out hydro stop functions with Norton Roadholder factory bushes, this of course leaves the spring too short so a gap of 2" must /should be filled and everyone and their sister always put in a longer solid bush to bare on spring which shoots the 2" gain in the forks, til I stuck in a valve spring and now kit sold by Greg Fauth. May be better out there and glad of it, but I'm out to take on moderns on/off road and know my tool of choice. I've welded up busted in half Roadholders that worked fine after so maybe stick in a segment for a new way to skin this forking cat. Of course can always take the easy way out by abandoning Norton.

xbacksideslider said:

Seems to me that our forks' sliders are too short, that there is too little distance between the bushings.

So, just wondering, has anyone made, or attempted to make, screw in extensions that would provide more distance between the bushings and move the seals up by the same amount.

Click to expand...

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.

Matchless said:

I have often thought the same thing, & my suspicions were confirmed when I took a pair of forks to Maxton Engineering for mods. Ron Williams told me the reason for this . Roadholders & most other British forks were designed to use external springs. If the sliders had been made longer there wouldn't have been enough spring room. Longer sliders would make the forks more rigid & less prone to stiction. (as indeed would modern bushes)
Martyn.

Click to expand...

This sounds like bollocks to me. You are (or Ron is) suggesting the forks were designed around the spring? The engineers would design the forks first, based on, amongst other things, required travel and then design the springs, calculating wire diameter, OD, number of active coils to provide required spring rate and to fit in the available space. Apparently there are advantages of a large OD spring (typically external) in comparison to a smaller OD spring (typically internal) but I'm not sure of the reasoning - possibly larger OD springs are more responsive in comparison to smaller OD spring of same rate and length or have better inherent damping.

Those long skinny springs would surely want to go snake and rub up to damper-rod and even inner fork tubes upon braking methinks, The much stiffer shorter outer springs would resist all the flexings ?

I think the Norman Hyde fork brace kit used extension pieces inc extra bushes to mount the brace onto, if my memory serves me well.
Not sure if they're still available though, but I'm sure they'll come p on eBay etc.

They Hyde fork brace moves the seal up 3" or so. No bushing movement. When they do come up expect to pay around $600.

Fork braces on Commandos and some others and reasons not seen more often.
https://www.google.com/#q=fork+braces+accessnorton

I first made the extensions for my interstate after replacing the staunchions, to give a greater length between the bearing surfaces with the idea of reducing the load at upper bushes, the bearing material is bronze filled teflon, they are a screw in replacement and use the standard seals, the dust caps on the interstate are from a RD yamaha, on the racer I uesd the stock items, after fifteen years of use there is no evidence of wear on the chrome of the staunchions, the system worked well so I made a set for the racer also. you may dispute the pro's and con's of this idea but part of my motivation is I just love to tinker with stuff on the lathe. and no I cannot make some for you till I get a decent lathe

Doesn’t the fork top hit the bottom fork yolk sooner then :?:

fredful said:

I first made the extensions for my interstate after replacing the staunchions, to give a greater length between the bearing surfaces with the idea of reducing the load at upper bushes, the bearing material is bronze filled teflon, they are a screw in replacement and use the standard seals, the dust caps on the interstate are from a RD yamaha, on the racer I uesd the stock items, after fifteen years of use there is no evidence of wear on the chrome of the staunchions, the system worked well so I made a set for the racer also. you may dispute the pro's and con's of this idea but part of my motivation is I just love to tinker with stuff on the lathe. and no I cannot make some for you till I get a decent lathe

Click to expand...

Did you just duplicate the existing parts and put some space inbetween? Great job and I know from experience that this makes for much better workng forks with smoother travel (low friction and reduced binding).

Very clever and impress slider extension Fred. Did you provide for 2" extra travel too? Much as it goes against normal logic grain, you simply can not laterally load forks to matter to need more support when extended fully as the spring rate is so light at that point the forks will 'instantly' compress a good ways before much lateral force can develop. Not theory but fully tested fact. I may be the only one to actually bend normal Roadholders in full extension when the deer strike knocked bike out from under sideways and left deer fur completely around embedded in full PSI tire bead then landed hard nose down on them next instant later. I have tested Peels even hard blasting full extended 50's mph through over hanging lip of goofer hole hidden in pasture grass to obsure vision in explosion of sod clods and dirt spray that launched us air borne 3 ft and land nose low slapping my helmet chin on the yokes, still perfect alignment function as prior. Several lighter ways to skin the Roadholder cat.

2in more travel and it would hit the lower triple clamp. The idea isn't to get more travel, just to support the stanchions better.

Neat to see the slick extensions but a solution to a imaginary weakness issue and 2" more travel would not be appreciated by most anyway. I dare ya Swoohie to give-find another example besides mine of bending/damaging forks in full extension. Your distracted car rear end smack is perfect example of conditions strong enough to hurt forks, that is mostly compressed if not fully already. I don't think less of you for smacking into a car, crap me too almost from an instant look away but i managed to veer along side of car, feeling luckier than you I had room that time is all. You all's fault in logic assumes the forks need fextra support when unloaded full extended but duh they can only be full extended when fully unloaded so no load to hurt a thing, till soon after of course. Duh yep the forks are most weak state at full extension but the wise Norton designers made em tough enough its a non issue, thank goodness. I had to consider all this on lighttening up Peel at same time as adding stuff on forks. If you are riding hard enough to appreciate any improvement in factory Roadholders you should be ashamed of yourself risking a quain't motorcycle and pilot for so little thrill gained on an un-tammed isolastic rubber baby buggy. Now if you are now and then powering over rough enough, windy enough, long enough turn to actually onset wobble, FOR SURE any and Every improvement of Roadholder will instantly be apparent and hopefully worth while enough to recover not to be caught out like that again, no Sir REE Bob!

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.

Click to expand...

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

Bernhard wrote:
Doesn’t the fork top hit the bottom fork yolk sooner then :?:

No they still miss the bottom of the yokes by about an inch

Jim wrote:
Did you just duplicate the existing parts and put some space inbetween? Great job and I know from experience that this makes for much better workng forks with smoother travel (low friction and reduced binding).

It was a long while ago I made them and there are some detail changes regarding the bushes but the seal retainers are the same
Fred.