Forget P.T.F.E fork bush.s just add it.

The idea of super slippy fork P.T.F.E based bush's sounds great, but the draw back is the materials lack of suitability,...So why not just add a mixture of slick fifty [P.T.F.E based] and 5 sae oil?

Any comments? or as anyone done this,,,and if so what was the result?

Gday John, not a bad idea about the slick50. How about soaking the bush in slick whilst its heated rather than run it in the forks? You would have to be careful not to breath in any poisonous fumes though!
Rgds Foxy

Foxy, I guess you have not tried this we up here have enough fumes/dust from the bleedin volcano! Anyway hows the dampers, got them sorted ? John

Slick 50?

When Slick 50 came out DuPont (patent-holder of Teflon) stated that such use of Teflon was not appropriate. Slick 50's "engines running without oil" advertisements that were on TV have been shown to be marketing cr@p and they lost a judgement to the US Federal Trade Comission re that. There have also been reported cases of the stuff clogging oil filters.

Per the US Federal Trade Commission statement, "Blue Corral, the manufacturers of the Slick 50 engine oil additive, have been banned by the Federal Trade Commission from making claims about reduced engine wear, increased fuel economy and lower running temperatures in it's advertising in America."

It would seem to me that a teflon-edged fork seal might be useful but since it's been proven that slick 50 doesn't reduce friction, I don't think there is any benefit to using it for this (or anything else).

Seems like that crap would be too thick for fork oil application. Mixing oils of different viscosity doesn't produce a different oil of median viscosity, only regions of each different viscosity.

Hi Not to sure you are correct in the viscosity statement, Thame's oil blends 10 's 50% and 20's 50% to make 15 grade hydraulic,and have do it for 40 years. i have not mixed slick with fork oil, but as it is mineral based i recon they will mix, mayby 10% slick and 80% fork fluid, perhap's i should suck it and see?....but how do i measure and record the results.

Danno said:

Seems like that crap would be too thick for fork oil application. Mixing oils of different viscosity doesn't produce a different oil of median viscosity, only regions of each different viscosity.

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John — Some fork stanchions of the period, e.g. Marzocchis and Cerianis, ran directly in the the alloy. Seeing that the top bush is well lubricated, could you use an aluminium alloy top bush instead of sintered bronze? Or would there be excessive wear if the stanchion ran on only 1.5 inches of alloy (or 2.5 inches if you extended them)? Would scrolling the bush help? I have a set of period Cerianis on a Ducati where the stanchions slide directly in the alloy and there is minimal stiction as long as the dust covers are removed. The advantage I see is that you could machine some suitable alloy to a very fine finish and achieve a closer fit on the stanchion than with the standard sintered bushes from Andover. This would prevent the stanchion from becoming cocked in the fork leg, which causes what appears to be stiction but is actually slight binding, as you have correctly observed. A fork leg with a sloppy top bush will slide up and down freely on the bench but once you put a side load on it, it will bind slightly.

Any views?

Dave

David. I would imagin your alloy bush would be fine. honda cams run directly in the head, I have ordered some Oilon thick wall tube to make some for a triumph, Google it ...its slighly more sticky than ptfe,,,but wears 25 times better than bronze! and easy to machine [with sharp tools]
Again the subject of binding crops up...One thing i must check is the wheel spindle alignment,,,,? If the hole centre's are not "Blind on" the forks are out of true to each other! Think about it, WHERE THESE EVER RIGHT in the first place :?: ...Infact i will do a check today and see. Regards John

John — When I did a search for suitable materials, I came across Igus. You may know of them. Have a look at their site:
http://www.igus.co.uk/default.asp?Page= ... &C=GB&L=en

I did not put in an order because I wasn't fully confident of my machining ability with plastics. They are in Northampton, not a million miles from you. They make plastic bearings for a range of applications, including for hard chrome surfaces. They do flanged bushes in inch and metric sizes but I think you would end up machining them to fit. Or they may sell you bar stock. However, they may be willing to make one-offs. If you could convince them to make a pair of bushes to your specs, they could end up selling you a load more if they worked, since you could do the bushes as part of your fork damper conversion. Why not talk to them and see what they have to say?

Dave

I have ordered some Oilon thick wall tube to make some for a triumph,

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When I worked in R&DD I machined a lot of these then exotic plastics and I'm sure those like Oilon swell as they absorbe fluid. I'm also sure there was a table available that gave the correct clearance that would allow for any reduction in diameter.

Cash.

Believe me or don't - but the road loads are orders of magnitude
over any binding restriction detectable in usage with oil
in forks and intact bushes of any sort.

A factor seeming ignored is the un-binding action or
road going vibration. Induced vibration is used to
un-bind many otherwise friction limited sliding.

The slack in the bushes-tubes can be detected by static
push pull on forks with a slight motion at tire patch.
I hunted reason for this after observing Peels' forks blurring
in fro/aft vibration on hi powered fast turns in tights.
I believe its enough added vibration to help tire
loose grip, unless going in harder to lift front
out of significant traction interference.
I now know better to ever try this on non rear linked
Commando, beware!
I now know better to ever try this on best moderns too.

Oil spiral grooves good idea I found in pre-Peel on first
opening a decade ago.

hobot