Fork repair discussion WideGlide

Stiction, other issues

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Hogey
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Re: Fork repair discussion WideGlide

#31

Post by Hogey »

Excalibur wrote: Fri Sep 16, 2022 11:35 am Made a decent improvement to stiction by carefully tickling axle bore holes in fork sliders. As it was, both axle bores were fighting each other making axle banana shape.

Studying existing seals, they dont have any lip springs so I ordered some that have them both sides. I can see why they'd reduce stiction. But lets see, they at least 9 days away.

Question, is there a fork oil that really does reduce friction? Claims and sales pitch are easy to make but what does the brains trust think? Not trying to start an oil war :roll: but I run Motul in the Pan forks.

Oh and by the way, I was out on my '61 Pan today and I'm absolutely loving its' Gold Valve suspension. Makes my earlier struggle all worth while.

The Shovel will be easier to convert to Gold Valve, no machining up parts. There is a question mark about suitable fork spring rate. Website says 1kg/mm. I suppose I could measure up existing ones or simply fit them and see. Worst case scenario, order another pair of springs. For compare the Pan has 0.9kg/mm springs.
Dont go with race tech spring rate way to Stiff. for Sh-t roads
Hogey
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Re: Fork repair discussion WideGlide

#32

Post by Hogey »

Excalibur wrote: Fri Sep 16, 2022 11:35 am Made a decent improvement to stiction by carefully tickling axle bore holes in fork sliders. As it was, both axle bores were fighting each other making axle banana shape.

Studying existing seals, they dont have any lip springs so I ordered some that have them both sides. I can see why they'd reduce stiction. But lets see, they at least 9 days away.

Question, is there a fork oil that really does reduce friction? Claims and sales pitch are easy to make but what does the brains trust think? Not trying to start an oil war :roll: but I run Motul in the Pan forks.

Oh and by the way, I was out on my '61 Pan today and I'm absolutely loving its' Gold Valve suspension. Makes my earlier struggle all worth while.

The Shovel will be easier to convert to Gold Valve, no machining up parts. There is a question mark about suitable fork spring rate. Website says 1kg/mm. I suppose I could measure up existing ones or simply fit them and see. Worst case scenario, order another pair of springs. For compare the Pan has 0.9kg/mm springs.
i have motul in most grades but what i surprise the penrite Synthetic made to reduce friction. i have used it customers bikes with out letting on and get what did ya do to the forks :wink:
Excalibur
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Re: Fork repair discussion WideGlide

#33

Post by Excalibur »

Seals arrived, took 14 days. We were laughing,. It took 7 days to do 6900miles, then another 7 to do next 100miles. Seals seem really good. Low friction compared to ones coming out. Thanks for the tip Ray, these will do nicely. They have garter springs, 11mm thick so I need a 2mm thicker washer under retaining ring.
Have one old seal out so far. Was a fight. Ended up using a dremel, weakening the seal to the point where it gave in. Is there a better idea? Perhaps heat?

Have decided to cut fork tubes down to standard length using my lathe with a steady.. Biggest problem is my lathe was always missing the metric thread gear set and by the time I realized, seller had died. Anyway I found a couple of gears in the right ratio pairing, only they need boring to suit the shafts plus keyways.

Did a quick measurement of existing fork spring weight. They are 0.8kg/mm at the most. Racetech site says 1.0kg/mm. Going to try the existing 0.8's and hope they're good enough. If not, I have 2 choices. Either buy a pair or increase compression dampening. The latter is not ideal as it goes back toward how conventional damper rod forks are set up.
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Re: Fork repair discussion WideGlide

#34

Post by RooDog »

Ate you gonna shorten the tubes from the threaded top, or the counter bored bottom?
Excalibur
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Re: Fork repair discussion WideGlide

#35

Post by Excalibur »

RooDog wrote: Fri Sep 30, 2022 2:47 pm Ate you gonna shorten the tubes from the threaded top, or the counter bored bottom?
Plan was to shorten from top hence the need for lathe metric re-thread. How do-able is it from the bottom.? Looks like some sort of crimping holding the pieces in plus there's the bleed hole to contend with. I had originally dismissed this prospect.... :?:

Funny story. About 30+years ago, my now long gone '80 FXEF was a bit weepy at its' fork seals so I picked some up from local supply. Once fitted I was frustrated with the added stiction. Initially I thought they could free up with use, but of course they didn't. My workaround was simple. I lifted the dust covers and wrapped several turns of cotton cloth strip. This was oiled kind of like a wick. It lubricated the seals from above and gave a welcome improvement in fork action. Once a month or so, I would lift the dust covers and re-oil. Bike stayed liked that and was eventually sold c1993. Some time later I spoke to the new owner, asking if he'd found rag strip wrapped under fork dust covers? He said yes and thought I'd done it to mop up leaky seals. :)
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Re: Fork repair discussion WideGlide

#36

Post by RooDog »

Excalibur wrote: Fri Sep 30, 2022 11:42 pm
RooDog wrote: Fri Sep 30, 2022 2:47 pm Ate you gonna shorten the tubes from the threaded top, or the counter bored bottom?
Plan was to shorten from top hence the need for lathe metric re-thread. How do-able is it from the bottom.? Looks like some sort of crimping holding the pieces in plus there's the bleed hole to contend with. I had originally dismissed this prospect.... :?:

Silly me, I thought you were working with vintage Hydra-Glide fork tubes.... I was confused by your needing metric threads....
Excalibur
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Re: Fork repair discussion WideGlide

#37

Post by Excalibur »

Making good progress on this old war horse. Front end is reassembled and installed with Gold Valving and existing fork springs.

Main points of interest:
I didn't shorten and rethread the fork tubes, though I did cut 1/8" from the tops. The fork tube top threads were such a loose fit I decided to trim 1/8" to gain deeper thread engagement. Perhaps worse though is the top thread and counter boring isn't very true to tube outer. Yeah, poorly made repop . When tubes were fitted to trees, I rotated each by hand to find its' happy place. It was sorta tight and loose as rotated. Plan is to mark the position/s so they always go back same way.

Fork slider axle bores were not true. Neither to the tubes nor to each other. Effectively the axle had a bend when axle nut and clamp was tightened. The clamp side was easy. Only the upper half was doctored and the lower would simply self align to it.
The nut side was more work. The hole was carefully tweaked to achieve axle at 90° to tube. Inner and outer faces of LH slider were whittled according to witness marking.

New Chinese fork seals are great, much less stiction and a difference easy to feel. Cheap too, just $4.33 USD pair, free shipping from China.

Next job is to make a fork tube alignment jig. For years I used simple eyeometer but a jig should be super accurate. I have the steel put aside at work.

Adjustment thoughts. Bike gives too much feedback from hard edge bumps though it's significantly better than before. Plan is to reduce compression damping pop pressure. I'd like even less stiction but might have to be satisfied with the step I've made.

If proper Showa forks turned up, I might have to think about the prospect. I suppose that means I'd need '80 - '83 FXWG. FLH ran the banana so mounts would be different plus tubes are short. What about Evo Softail?, ok brakes are different but would they otherwise fit??
Never know what's about to turn up...
stt7.jpg
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RooDog
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Re: Fork repair discussion WideGlide

#38

Post by RooDog »

Most any "41 mm" fork leg assemblies from 1949 HydraGlide up well into the Evo and Twinkie applications will fit into fork trees. So just keep you eyes open for what may be available at a reasonable price. Based on the stock length of the standard 1949 HydraGlide, the FX ST legs are + 4 inches. The FL ST legs are a pleasant + 2 inches, and give good ground clearance with out being overly extended. I have no experience with the big late model Touring forks, but beware, some of them have internal cartridge damping on one side only. And of course you'll also have to consider the wheel, axle, and braking.
Personally, I like the FXST legs on my '68 FL street hot rod...
....RooDog....
Excalibur
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Re: Fork repair discussion WideGlide

#39

Post by Excalibur »

Update with some good, pleasing progress. The solutions were in a number of steps which I'll itemize in detail. After initial tweaks, I was still getting 35mm of stiction. The main problem was the pounding the rider received on hard edge bumps. The forks were not compressing easy enough and the impact gets transferred to rider, with an unpleasant jolt. Not quite winding the rider but something toward that effect. The plan is to reduce stiction by any and every trick. Also reduce compression damping to the point where the spring takes the impact shock by coil compression whereas before it would hit rider in the midsection and buck the front of the bike. However on soft-edge, shallow bumps, forks would move as expected. It's when the forks were asked to compress quickly, they resisted. I reasoned the problem was stiction or compression damping or a combination of these two.

I made a solid distance piece tool, to measure the legs for being parallel. This was like using an inside micrometer but a fixed length. In this way I was able to understand, the legs were slightly splayed.

I used an old drill press table-plate to check fork tubes were parallel to each other when viewed from the side. Historically I used to simply eyeball this, but the little machine-finished table took it to another level.

The top fork tube plugs were not concentric to the tube itself. At least some of the problem was in the tube thread, it was off center. To fix this, I screwed the plug in tight, then put the tube in the lathe, holding the top end in a steady. At this stage it was obvious how far out of true the assembly was so I turned some material away. Clearly it would be slightly loose in the top tree but that was better than being somewhat bow legged.
These are repop, so I simply did what I had to do. I marked the parts so that in my ownership, they will always go together according to markings.

I read about low friction fork seals made by SKF, green color. They are $40USD a side. Not cheap but they made a very noticeable difference when comparing by hand against existing seals. These new, SKF seals were not listed as fitting a FXWG or any Harley but I was able to verify inner and outer dimensions. I did not care what the thickness was because I'd make spacers to suit. Their dust seals weren't used.
skf1.jpg
I pulled the Gold Valves, removed the recommended compression damping springs and replaced them with the lightest ones in the kit, setting them just 2 turns of preload.

After hearing how noisy the dry fork springs were I polished the fork spring outers with fine wet and dry. In hindsight I could have smoothed the tube bores with a wheel cylinder hone though never did. How much difference all this made isn't clear but at least I tried and I was after any little edge.

I researched oils, looking for any small margin of reduced friction. I settled on synthetic fork oil by Motul (Factory Line). I chose 10w, their heaviest in full synthethic. Because Motul only goes to 10w I subsequently swapped to Putoline for a 15w, also full syn.

Fork tube treatment. PTFE Teflon spray was tipped as an aid to reducing stiction. Apparently racebike guys use it. Of the types I had on hand Dry Glide seemed to have superior film residue so I've been applying that before every ride.
PTFE grease was the next thing to try and this worked very well on sponge rubber strips under the dust caps. In the pics, you can see it was a bit messy in initial trials but am hoping I can wipe off the surplus and the residual teflon will be good for some hundreds of miles.
ptfe1.jpg
Result to date. Front end has transformed. Am getting much better response to hard edge bumps. The front has been freeing up so much that rebound damping was becoming insufficient. Tonight I've just swapped in 15w full synthetic fork oil.

Stiction has reduced to 16mm 5/8".

More pics and info are on my Shovel blog plus I'll be updating there with any developments.

Hope all this is interesting or it helps anyone. It's taken quite a while to compile this info and much longer to action the steps. Still learning so let's see. Happy to hear from anyone who has any thoughts, ideas, experiences, proven tips etc. Thanks.
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Hogey
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Re: Fork repair discussion WideGlide

#40

Post by Hogey »

Been a while thought id check in and see how its going. Ya happy with mods ?
Excalibur
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Re: Fork repair discussion WideGlide

#41

Post by Excalibur »

Hogey wrote: Tue Mar 28, 2023 9:41 am Been a while thought id check in and see how its going. Ya happy with mods ?
Yes, very happy with progress. Am about to experiment with reducing compression damping setting some more. What's not clear is how much remaining stiction is affecting "hit" on hard edge bumps and how much compression damping setting is affecting it. If I never get any more improvement I could live with it. Earlier it was so bad I seriously considered swapping the tubes and sliders for perhaps Softail. Now with suspension starting to come along and I have the brakes working too, am settling on sticking with what I have.

You guys like pictures, right?

Riding with local classic club Sunday. Leaving for a shed raid to see some nice Nortons and a bunch of other cool stuff.
wcc1.jpg
Out testing fork oil level change, true story. Stopped for Panhead Hazy IPA on tap at our local 8)
wcc2.jpg
Getcha motor runnin' :P
wcc3.jpg
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Hogey
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Re: Fork repair discussion WideGlide

#42

Post by Hogey »

:D Thanks for sharing mate.
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