Alloy slider front fork improvements

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Alloy slider front fork improvements

Post by Didlydon » Thu Sep 14, 2017 4:00 pm

Hi All

I've read threads about front fork improvements by doing stuff to the dampers & putting expensive emulators in em, but putting it simply I want to improve the action for road use, in the simplest & cheapest way. What have you done to yours that works! Pumping them up & down they seem quite soft in action but on the road they just don't seem to react over the normal little bumps & ripples - stiction? - Is it worth replacing the O ring on the damper assembly with the phenolic rings from LP Williams to help with this?

On my T150V Trident I had the dampers modified by Richard Darby (3D Motorcycles) in the UK, which involved welding up the slots in the dampers & cross drilling holes in different places - which worked well for a heavy bike. As the dampers are the same I'm guessing the same mods would work on the B50? Anyone with the technical info on what to do here please ? Favorite super slippy anti stiction oils anyone?! :smile:

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Re: Alloy slider front fork improvements

Post by minetymenace » Thu Sep 14, 2017 4:55 pm

Didlydon wrote:in the simplest & cheapest way
The age of the bikes means that the parts are either worn out or replaced. The cheapest is to carefully rebuild replacing the out of tolerance (through use or bad replacements) and maybe spending a bit more (say at L&P0).

With the standard forks you can put spacers in to adjust the pre-load, alter the spring rate and change the oil viscosity to adjust the compression damping. All of this was available to BSA when the bikes were built, and the production setup was as good as it could be for the time (except perhaps for progressive fork springs).

If you hadn’t made the statement about simplicity and cheapness, you could benefit from 40 years of motorcycle suspension design and bring the front end suspension into the 21st century. Maxton (amongst others) will update your front end and give you the benefit of optimum spring rate, adjustable pre-load and both compression and rebound damping, all hidden in your existing tubes. You can then spend hours tinkering with minute adjustments that make imperceptible differences to the suspension.

The thing about riding on the road is that the conditions vary, twisty leaf strewn B roads one minute become fast A roads the next and any suspension setup is going to be a compromise. Racing is different, the surface is normally consistent and you might make tweaks for different tracks, but on the road your setting, once set, will remain unchanged (maybe the odd course adjustment for pillion or camping gear).

I’d rebuild with care (measuring everything and replacing worn parts) and fit progressive springs, fork oil will mix so you can progressively vary the compression damping if you want to try fine tuning on the cheap.

Yes, I have been down the Maxton route when I had money to burn, but I’m not a good enough rider to appreciate the difference, it gives you more confidence but it doesn’t stop you falling off!
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Re: Alloy slider front fork improvements

Post by Didlydon » Tue Sep 19, 2017 12:51 pm

Thanks Minety for the comprehensive reply. I rebuilt the front end with lots of new components, including MX stanchions & new old stock springs. The old dampers were pretty buggered about with & corroded, with odd springs fitted. Its a job for the winter I reckon as the new Emgo seals are weeping a little already & I reckon I'll replace the damper O rings with the supposedly better tufnol ring type from LPW. Supple.....that's what we're after! :grin:

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Re: Alloy slider front fork improvements

Post by minetymenace » Tue Sep 19, 2017 3:13 pm

A word of warning and it may be urban myth, modern tubing is ground down so that the OD is correct(ish), however the internal diameter may be different, make sure the new damper O-rings or whatever seal you are using is a good fit on the ID...
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Re: Alloy slider front fork improvements

Post by midgie » Tue Sep 19, 2017 6:46 pm

I have found this on pattern stanchions, not only are they undersize on the o/d, they are oversize on the I/d so the correct o ring on the damper valve dosent make contact.

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Re: Alloy slider front fork improvements

Post by B44Claus » Thu Sep 28, 2017 11:03 pm

I just realised that the new stanchions I bought earlier this year are undersize! Extremely dissapointed :(
They should be 1.3610-1.3605. However they measure 1.3604 as if they were worn beyond tolerance. Combined with fork legs that also a bit worn the whole assembly becomes wobbly.
I should have measured them at arrival but didn't as I bought from a trusted vendor. Perhaps they will take them back.
Anyone knows where to get stanchions in the correct dimension?

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Re: Alloy slider front fork improvements

Post by midgie » Fri Sep 29, 2017 7:48 am

I have been saying this for years about pattern stanchions. this is why I had my genuine old ones re hard chromed by philpots in luton. they were on warning that they must be 1.631" finished dia. as soon as they came back I was out with the micrometer. and yes they are spot on. mind you it did take 3 months! you will also find with most pattern stanchions that not only are they undersize on the o/d they are o/s on the I/d. so the o ring on the damper valve makes little or no contact. the joys of pattern parts!

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Re: Alloy slider front fork improvements

Post by midgie » Fri Sep 29, 2017 7:50 am

midgie wrote:I have been saying this for years about pattern stanchions. this is why I had my genuine old ones re hard chromed by philpots in luton. they were on warning that they must be 1.631" finished dia. as soon as they came back I was out with the micrometer. and yes they are spot on. mind you it did take 3 months! you will also find with most pattern stanchions that not only are they undersize on the o/d they are o/s on the I/d. so the o ring on the damper valve makes little or no contact. the joys of pattern parts!
its early! that should read 1.361" of course.

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Re: Alloy slider front fork improvements

Post by B44Claus » Fri Sep 29, 2017 11:10 am

The weird thing is that the old(original?) stanchions measures up at the correct diameter in the areas which are not worn through the hard-chrome.
I don't think it's an option for me to have the old stanchions re-chromed as they are slightly bend. I know you can have the stanchions straightened before hard-chroming but I'm not certain what that does to the mechanical properties of the steel and thereby to the strength of the fork assembly. Any experiences with that?

Another annoying issue with the pattern stanchions is that the lower yoke must be tightened more in order to clamp the stanchions properly. The old ones are a sliding fit in the yoke where the new are more loose.

Pattern parts are here to stay but why don't they manufacture them properly? It's no bigger effort to grind the stanchions to the right diameter than the wrong?!

There must be someone who has sourced new stanchions recently and have good experiences(I hope)? Please share with us :smile:

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Re: Alloy slider front fork improvements

Post by Victor500T » Fri Sep 29, 2017 12:33 pm

midgie wrote:I have been saying this for years about pattern stanchions. this is why I had my genuine old ones re hard chromed by philpots in luton. they were on warning that they must be 1.631" finished dia. as soon as they came back I was out with the micrometer. and yes they are spot on. mind you it did take 3 months! you will also find with most pattern stanchions that not only are they undersize on the o/d they are o/s on the I/d. so the o ring on the damper valve makes little or no contact. the joys of pattern parts!
I'm not the only one to find this then! I bought some supposedly NOS T140 stanchions only to find the inside diameter is way too large. Probably a good .010" gap between the O ring and the tube, therefore useless.

I'd use Philpotts service as I very much like the idea. Their prices are eye watering though!

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Re: Alloy slider front fork improvements

Post by midgie » Fri Sep 29, 2017 1:01 pm

The re chrome service which included their courier pick up from me and delivery back cost me £175. but I now have the genuine stanchions which I can use. buying pattern ones which you cant use is a no brainer.

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Re: Alloy slider front fork improvements

Post by Victor500T » Fri Sep 29, 2017 9:55 pm

That's the price I had Midgie. As you say, cheap stanchions that don't bloody fit are a total waste of money! But I have had several sets of modern pattern stanchions that have been OK, and about a third Philpott's price for rechroming.

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Re: Alloy slider front fork improvements

Post by B44Claus » Sat Sep 30, 2017 12:15 am

Hi,

The ones I bought weren't particular cheap. You can't always tell from the price if the parts you buy are useless cr**. That's why I was asking if members of this forum could point me in the right direction of where to get correct stanchions. Victor500T can you remember where you bought yours?

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Re: Alloy slider front fork improvements

Post by Victor500T » Sat Sep 30, 2017 6:55 pm

I got my 'good'one from Monty's Classics http://montysbritishclassicmotorcycles.com/ . I think I also got a pair from TMS http://www.tms-motorcycles.co.uk/ . Both specialise in Triumphs but the pre-disc OIF T120s had the same stanchions as our B50s, so shouldn't be any trouble. I agree with what you say about price not necessarily being a reliable guide to quality.

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Re: Alloy slider front fork improvements

Post by B44Claus » Mon Oct 02, 2017 8:01 am

Thanks for the information; Good point about Triumph forks sharing the same stanchions as the B50's. :thumb

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Re: Alloy slider front fork improvements

Post by lathejack » Thu Oct 05, 2017 11:32 pm

I bought a pair of new pattern stanchions a few months ago for my B50. After reading quite a while ago on this forum of some of the possible problems they can have I pointed this out to the seller. "No problem" he said, "just take them and check them and pay me if they are ok, if not just bring them beck when you can".
After a couple of months I still hadn't managed to find the time to strip my forks to check them properly, so I just paid him anyway.

During the last week I have finally managed to strip the forks and check the stanchions properly, and thankfully these are spot on.
They came in a plain brown box, with each stanchion individualy wrapped in anti corrosion paper and a polythene sleeve, I don't know where or by who they are made, but they have done a very good job.

The surface finish on them is superb, with very fine grinding and an O/D of 1.361. The internal bore is also correct, with the damper rod O rings having the same fit as they do in the original genuine stanchions.
The internal threads at both ends are also correct, as is the fit of the short external taper at the top when fitted into the top yolk.
image.jpg
In fact the superb and faultless very finely ground surface of these new pattern stanchions is superior to that on the genuine items on my B50.
My original stanchions have what looks like a turned finish visible below the chrome. One of them also has a course pitch cutting tool mark spiralling its way along the tube, caused by the rapid return feed rate of the tool carrage. This is just visible in this second photo, and can just be felt when running a finger nail along the tube.
Plus they have the usual wearing away of the chrome plate, which is something I have never encountered on a Japanese bike.
image.jpg

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Re: Alloy slider front fork improvements

Post by B44Claus » Fri Oct 06, 2017 12:01 am

Hi Lathejack,
Thanks for sharing this. Can you also let us know the sellers name?

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Re: Alloy slider front fork improvements

Post by minetymenace » Fri Oct 06, 2017 7:57 am

Ditto
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Re: Alloy slider front fork improvements

Post by midgie » Fri Oct 06, 2017 1:19 pm

minetymenace wrote:Ditto
midgie +1

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Re: Alloy slider front fork improvements

Post by Victor500T » Sat Oct 07, 2017 1:08 pm

Did you get them from TMS, Lathejack? I bought mine from there and they came in identical packaging and also look top quality (and fit properly!)

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Re: Alloy slider front fork improvements

Post by kommando » Sat Oct 07, 2017 2:34 pm

The marking on the anti rust paper will possibly show which country they were wrapped in. The packaging looks very much like the Emgo wrapping on my hard chromed T120 pre OIF stanchions I got from Feked.

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Re: Alloy slider front fork improvements

Post by lathejack » Sun Oct 08, 2017 12:33 am

I bought these stanchions from a seller at the Autojumble I visit, he did say he had more of them.
I have his business card somewhere, I just can't find the damn thing at the moment.

The writing on the paper wrapping is in English as well as Far Eastern.

When the dampers are slid inside the pattern stanchions the O rings grip the bores to what feels like the same extent as they do in the genuine items. But I will measure the I/D properly, just to see if there is any difference.

it isn't until examining these beautiful looking pattern stanchions that the somewhat rough and ready appearance, here and there, of the genuine items really stands out.
Ignoring the wear on the originals, when placed next to the pattern items, if you didn't know which was which, you could easily be convinced that the pattern stanchions were the genuine UK made article.

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Re: Alloy slider front fork improvements

Post by JB » Sun Oct 08, 2017 10:55 am

Lathejack, out of interest would you say that the chrome on the original stanchions is hard chrome? I seem to recall that BSA/Triumph used decorative chrome rather than duller looking hard chrome and is why the chrome wears off so easily on the originals??

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Re: Alloy slider front fork improvements

Post by lathejack » Mon Oct 09, 2017 9:34 pm

JB wrote:Lathejack, out of interest would you say that the chrome on the original stanchions is hard chrome? I seem to recall that BSA/Triumph used decorative chrome rather than duller looking hard chrome and is why the chrome wears off so easily on the originals??
Yes, it does look more like a decorative Chrome finish, rather than a more purposeful and functional precision ground Chrome surface.
I think all Chrome is the same hardness, whether it is just decorative Chrome plate or that described as hard Chrome.
It is probably just the way it is applied and its thickness that gives it the necessary wear resistance.

But I agree that there is something not quite right with the original genuine stanchions of the OIF bikes, I have seen so many of them worn out.
I have had a T140 and T150, as well as my B50 all with the same totally worn away Chrome, revealing the Nickel or Copper base layer. So maybe the original chrome is simply too thin for the job it is supposed to do, and not helped by the stanchions rather rough looking machined surface under the Chrome plating on some examples.

So although these new pattern stanchions are the correct dimensions, and have a far superior surface finish compared to the genuine items, it will be interesting to see how well the Chrome lasts in use.

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Re: Alloy slider front fork improvements

Post by JB » Mon Oct 09, 2017 11:11 pm

I must admit I never knew the difference between hard and decorative chrome plating other than knowing they are different for obvious reasons.
A bit of searching found this.

Decorative chrome plating is sometimes called nickel-chrome plating because it always involves electroplating nickel onto the object before plating the chrome (it sometimes also involves electroplating copper onto the object before the nickel, too). The nickel plating provides the smoothness, much of the corrosion resistance, and most of the reflectivity. The chrome plating is exceptionally thin, measured in millionths of an inch rather than in thousandths.

Hard chrome plating is chrome plating that has been applied as a fairly heavy coating (usually measured in thousandths of an inch) for wear resistance, lubricity, oil retention, and other 'wear' purposes.

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Re: Alloy slider front fork improvements

Post by skippy » Tue Oct 10, 2017 2:45 am

I had stanchions chromed at bendigo for my Z200, cost $100 and so far they are working OK. Hard chrome in Queensland cost $400. The old Z200 was not worth the cost of hard chrome.
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Re: Alloy slider front fork improvements

Post by Victor500T » Tue Oct 10, 2017 9:03 pm

lathejack wrote:
JB wrote: So although these new pattern stanchions are the correct dimensions, and have a far superior surface finish compared to the genuine items, it will be interesting to see how well the Chrome lasts in use.

I've done about 2500 miles on my TR7 with a pair of the good-looking stanchions. So far, so good. Which is more than I can say for the pair I fitted originally. They were much shinier but the seals leaked from the start - the right one quite a lot (left one was just a weep). I tried 3 different types of seals, always imagining it was them to blame. Turned out it was crap stanchions. they were supposedly LF Harris, incidentally.

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