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#677879 - 12/15/16 11:44 pm Excessive Fork Play?  
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Chris Battle Offline
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Chris Battle  Offline
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Coffs Harbour, NSW, Australia
Hello Brit Bikers,

If I put my bike on its stand so that the front wheel is off the ground, and push and pull on the bottoms of the fork leg sliders, is it OK to feel a bit of play between the fork leg sliders and the stanchion tubes, or should it feel "solid"?

I've been restoring my 1972 Triumph 500 T100R, and I believe that the 650's had the same forks up until the O.I.F. models. Presumably my forks are the same in principle to the BSA and Norton, etc.

At present, I have taken the forks apart, and have fitted new stanchion tubes and bushes. However, the bushes seem a very loose fit on the stanchions. I've put the forks together without oil or springs, and have installed them back on the bike. There is no play in the steering head bearings. With the fork leg sliders extended all the way down, I can feel and see almost 1mm of play, when pushing and pulling, back and forth, from the bottom of the sliders. Would this be normal?

I understand that forks of that era had fairly wide clearances between all the components, so I don't know whether or not play should be felt when performing the above test. The fork leg sliders (bottom member) may well have a reasonable amount of wear within the bore, after some 40 years of use.

I'd appreciate any feedback to my question.

Cheers,

CB.

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#677888 - 12/16/16 2:26 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Stuart Online content
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Hi Chris,

Firstly, welcome to this Forum. smile

Originally Posted By Chris Battle
I understand that forks of that era had fairly wide clearances between all the components, so I don't know whether or not play should be felt when performing the above test.

Aiu John Healy's answer in the TriumphRat CVV forum, if all the fork parts you have are within the specs. given in the workshop manual then, 'fraid yes. frown

If some or all of the parts are towards the workshop manual limits, clearances will be wide. If you know a machinist who can bore and turn accurately, (s)he can make bushes with smaller ID and larger OD to reduce the clearances but, aiu John, if you close up the clearances too much, you risk introducing excessive friction because stanchions and sliders aren't precisely parallel. frown

Ime, realistically, if the parts you have are within the specs. in the manual, but you would like to reduce the discernible play, afaict your best option would be to make/have made new bushes to reduce the clearances to the minima in the workshop manual, fit them and, if that causes too much friction, bore and turn the bushes by whatever minima you/the machinist can work to and reassemble the forks, doing that possibly several times until the friction disappears. If that sounds tedious, ... frown

In the earlier CVV thread I referred to, the OP received parts that were either close to or actually outside the manual limits; iirc, he closed them up by having new bushes made to work with the stanchions and sliders he'd been sent. However, I don't remember him returning to the thread to detail how close he'd made the clearances/how many fits/refits it'd needed.

Hth.

Regards,

#677891 - 12/16/16 3:14 am Re: Excessive Fork Play? [Re: Stuart]  
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Chris Battle Offline
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Coffs Harbour, NSW, Australia
Hi Stuart,

You've referred to a "TriumphRat CVV forum" and an "OP", can you please explain what "CVV" and "OP" are? I'm not up on the jargon.

I'm just wondering if anyone has every shaken the forks on their bike as I've described; and what was the result experienced?

CB.

#677893 - 12/16/16 3:34 am Re: Excessive Fork Play? [Re: Chris Battle]  
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kommando Online content
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Classic, vintage and veteran, original poster.

#677916 - 12/16/16 8:47 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Allan Gill Offline
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Rotherham - S. Yorkshire
Originally Posted By Chris Battle


I'm just wondering if anyone has every shaken the forks on their bike as I've described; and what was the result experienced?

CB.


Have you checked the play with the wheel fitted?


beerchug
#677941 - 12/16/16 1:16 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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John Healy Online content
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Further to what I said over on the Rat Forum these fork tubes are spindly and bend and twist going over uneven terrain and especially during braking. They twisted so bad on the first disk brake T140 that they broke fender braces. Those disc forks shared the same clearances as the earlier fork. If the clearances weren't as wide as they are the forks wouldn't function as the tubes bend and the fork twists.

If the fork bends or twists while going over rough terrain or during braking when tolerances are too tight it will hinder the fork action often causing them to momentarily freeze.

Triumph made a crude attempt stiffen the fork assembly with the 3 point fender brace replacing the front two fender braces, but they were still unable to close up the tolerances and have the fork work in all conditions.

Norman Hyde made an attempt to improve on the factory fork brace for the disc models but it was bulky, expensive and a bit of a bother to mount. Webco had one for the pre-1971 model which was effective, but industrial. It was used mostly by desert racers in the American South West.

Remember you must look at the design, and manufacture of these fork assemblies as a whole not just one piece, or one clearance. In effect the exercise was a series of compromises. The overall design changed little since the day they were introduced. They were made more to a price than a specification on equipment that would be laughed at today. Could they have used 38mm tubes, held tighter tolerances on the triple trees, changed how the axle held the wheel? Of course but change is expensive and for what ever reason that money wasn't available.

Can you tighten up the tolerance on the fork bushes? Yes, but you will have to address all of the faults that make this kind of tolerance necessary in the first place. Triumph was able to do this in the race shop, you can too.

The tolerances in the Workshop manual just don't come out of thin air. They reflect the reality of the design and the ability to produce them in production.


#677949 - 12/16/16 2:21 pm Re: Excessive Fork Play? [Re: John Healy]  
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Irish Swede Online content
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But John, Chris is referring to the steel-bottom forks used on 500cc bikes up to 1973, and 650s up to 1970, not the alloy-bottomed ones used 1971-on.

If he is having fork problems on a 500, something else must be
his problem. Is it simply bad busing tolerances anyway?

#677951 - 12/16/16 2:33 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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John Healy Online content
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Quote:
But John, Chris is referring to the steel-bottom forks used on 500cc bikes up to 1973


Chris is cross posting...

As I said above:
Quote:
Further to what I said over on the Rat Forum


see:

http://www.triumphrat.net/classic-vintage-and-veteran/787201-fork-play.html


#677960 - 12/16/16 4:24 pm Re: Excessive Fork Play? [Re: John Healy]  
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Thanks, John.

I went over to the RAT site and read your explanation.

I guess we can't "get it right," but we can get it CLOSE.

#677987 - 12/16/16 8:22 pm Re: Excessive Fork Play? [Re: Irish Swede]  
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Chris Battle Offline
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Coffs Harbour, NSW, Australia
Thanks, guys, for responses.

John Healy: The subject forks are indeed the ones as described by Irish Swede; steel sliders and not alloy. The reason for the "cross posting", is simply because I am looking for feedback as to detectable play in these kinds of forks. I don't know if I have a problem or not, and that is why I initially posted in TriumphRat, to find out what is "normal". I assumed I had a problem with my forks, because I read somewhere that no play should be detected when putting some reciprocating force (pushing and pulling) to the bottom of the forks when the wheel is off the ground. I appreciate the wealth of information you have contributed regarding the clearances of Triumph forks, but I'm still looking for any feedback regarding whether or not play should be detected, by the test given above, and if play is to be expected, then how much is too much?

kommando: Thanks for decoding jargon.

Allan Gill: No, I haven't checked for fork play with the wheel on; if I did prior to disassembly, I can't recall now. I'm just trying to sort out this matter while I have the forks apart and the components accessible, before I put the front end all together.

Irish Swede: Yes, I have the opportunity now, with forks disassembled, to get the clearances as close as possible whilst still allowing free fork travel. It would seem to me that this matter affects the handling of the bike, and that is why John Healy has made references to preparing bikes for racing.

Cheers..............CB.

#677992 - 12/16/16 9:39 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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Chris all of the information on the Rat site was about the early forks!!!!!

The information on the the disc models was added "further too what I said on the rat forum" to expand upon the points I was making on the other forum. Both forks share the same clearance specifications.

Most of the people who answer these types of questions monitor both (and others).

If you want to run less clearance you have to remove all of the reasons the so called "extra" or "excessive" clearance was put there in the first place. As I said about the video on the Rat site just because you can doesn't mean you should.

At this point you have the forks binding. Get them to move freely and take a thousandths of the clearance and check again. Remember under braking things bend requiring more clearance for the forks to move freely as you decelerate. So check with just the axle and then mount the wheel and do some braking tests. Repeat until you get the performance you want with the least amount of clearance. Or...


#678005 - 12/17/16 1:40 am Re: Excessive Fork Play? [Re: John Healy]  
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Chris Battle Offline
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John Healy:

Thank you for clearing up which forks you were referring to. I appreciate all the good material you have shared about the importance of working clearances on these kinds of forks, and I agree with you 100%.

But, what I am asking is, if there is a simple test that can be done in regard to finding whether there is excessive play between the fork leg sliders and the stanchion tubes, without having to disassemble the forks and measure the relevant components for clearances to check against the data published in the manual. For instance, pushing and pulling on the bottom of the forks when the wheel is off the ground. Has anybody out there ever done that, and if so, what did you find?

It would be a helpful reality check if someone who owns a British Bike would go out to that bike, perform the abovementioned test, and report back to us!

Cheers............CB.

#678010 - 12/17/16 3:45 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Stuart Online content
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Chris,

Originally Posted By Chris Battle
You've referred to a "TriumphRat CVV forum"

Originally Posted By Chris Battle
kommando: Thanks for decoding jargon.

On http://www.triumphrat.net/classic-vintage-and-veteran/, that by definition you have seen to post in that forum, immediately under the large Hinckley Triumph logo with "RAT.NET" above it, is:-

"Classic, Vintage & Veteran For Coventry and Meriden Models. Anything pre-Hinckley goes."

A word to the wise from someone who has got out of internet forums far more than he's put in.

Most of the questions on these forums are answered by a small number of people, all of whom voluntarily give up their time to help less-knowledgeable Britbike owners; e.g. John Healy, who has patiently repeated himself several times in two forums, is owner of US Triumph parts wholesaler Coventry Spares, owns TIOC, produces Vintage Bike magazine, moderates the Triumph Board on this Forum and contributes his knowledge to several other forums.

Normally it is said, "there are no stupid questions". Ime, if someone persistently tries to prove that statement wrong, that someone rapidly exhausts the patience of the volunteers who can answer his questions.

Another advantage of internet forums is previously-posted information can be retrieved by search software. I advised you how to do that on the TriumphRat CVV forum to answer some of your questions; however, after only the first search failed to return the information, rather than continue to follow my advice, you have simply posted your questions again and again.

As John Healy posted, "Most of the people who answer these types of questions monitor both [forums]". I respectfully suggest you read advice more carefully and consider what you post more carefully ... you wouldn't want people thinking you're insulting their intelligence?

Regards,

#678015 - 12/17/16 5:20 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Allan Gill Offline
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When I was MOT testing we had a lot of vintage bikes in, can't say that on the BSA or Triumph forks I ever found any disconcernable play when the front wheel was raised and the stanchions pulled back and forth. The main test was to check for play in the headstock but you would be able to feel anything else as like a bending


beerchug
#678020 - 12/17/16 5:40 am Re: Excessive Fork Play? [Re: Stuart]  
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Chris Battle Offline
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Coffs Harbour, NSW, Australia
Stuart:

Thank you for your advice, but with all due respect, I feel you are unfairly criticising me. The reason I posted on the Brit Bike Forum, under the title: "Excessive Fork Play?" was because no one was answering my question regarding detectable play in front forks. I was surprised when John Healy responded to my Brit Bike post with the same material he had contributed to my post on TriumphRat! I appreciate the material John Healy has contributed on the subject of clearances, and it is interesting and I agree with what he is saying, but what I am asking is a different question, and so far, no one has addressed it.

You have written:

"if someone persistently tries to prove that statement wrong, that someone rapidly exhausts the patience of the volunteers who can answer his questions."

Presumably you think I am that someone? I am clearly not that "someone", as I am not trying to prove anyone wrong, and certainly not John Healy. I'm simply asking a question, and we will all benefit if there can be an answer or answers forthcoming.

You have also written:

"Another advantage of internet forums is previously-posted information can be retrieved by search software. I advised you how to do that on the TriumphRat CVV forum to answer some of your questions; however, after only the first search failed to return the information, rather than continue to follow my advice, you have simply posted your questions again and again."

With respect, what you are saying about me has no foundation. I have found that the "search" tools of Brit Bike and TriumphRat just did not bring me any meaningful information. So, in the past I have searched answers to questions with "Google", and have been led to a number of posts and threads on this forum and TriumphRat, via Google's search engine. I did not, however, find anything relevant on this subject of play in forks, so that is why I originally posted on TriumphRat, hoping to get some answers to my questions on the subject of "fork play".

I think everything will become clear, for all concerned, if you can please re-read what I initially posted here on Brit Bike, under the title, "Excessive Fork Play?" and then respond back to this thread, citing my actual question. I think then all will be revealed, and oil will be poured on the turbulent waters of misunderstanding!

Cheers,............CB.

#678030 - 12/17/16 7:47 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Stuart Online content
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Chris,

<sigh>

Originally Posted By Chris Battle
I feel you are unfairly criticising me.

No.

The idiomatic English phrase, "A word to the wise" means "Here is some advice". Moreover I qualified it with my personal, first-hand experience, "from someone who has got out of internet forums far more than he's put in".

Originally Posted By Chris Battle
The reason I posted on the Brit Bike Forum, under the title: "Excessive Fork Play?" was because no one was answering my question regarding detectable play in front forks.

On the contrary, your question has been answered several times, you are just failing to understand the answers.

Originally Posted By Chris Battle
I was surprised when John Healy responded to my Brit Bike post with the same material he had contributed to my post on TriumphRat!
what I am asking is a different question

What you're asking for is "Yes" or "No". It doesn't exist. John and others have explained why "Yes" or "No" doesn't exist.

If you don't understand an answer, the best way for the poster to know that is if you post, "I don't understand". Otoh, ignoring an answer from someone like John Healy just because you don't understand it and asking the question again and again will not suddenly produce "Yes" or "No" but it might lead other readers - prospective responders - to less-flattering conclusions about you.

Originally Posted By Stuart
if someone persistently tries to prove that statement wrong, that someone rapidly exhausts the patience of the volunteers who can answer his questions.

Originally Posted By Chris Battle
Presumably you think I am that someone?

No. This is an open forum, anyone can read what's posted.

It was known long before internet forums that written English is notoriously bad at conveying tone, particularly in the absence of specifically-perjorative words. Nevertheless, that doesn't stop some readers applying a tone from their heads to words they didn't write and then attempting to have an argument about it. For reasons that should be obvious, that is just plain silly.

Originally Posted By Stuart
Another advantage of internet forums is previously-posted information can be retrieved by search software. I advised you how to do that on the TriumphRat CVV forum to answer some of your questions; however, after only the first search failed to return the information, rather than continue to follow my advice, you have simply posted your questions again and again.

Originally Posted By Chris Battle
I have found that the "search" tools of Brit Bike and TriumphRat just did not bring me any meaningful information.

Because you did not read the advice I posted carefully enough.

I know that the TriumphRat Search returns a maximum of 200 posts. That is specifically why I posted, "if the post/s isn't/aren't in the first 200, the Forum Search gives you date options to return earlier posts" - i.e. you read and set the options to exclude the latest 200 posts so up to 200 earlier ones can be returned. You want the information, you do the leg-work.

Originally Posted By Chris Battle
if you can please re-read what I initially posted here on Brit Bike, under the title, "Excessive Fork Play?"

Mmmm ... yes ... I'm not asking any questions, I understand the answers you've been given but I am supposed to re-read your posts ...

To reiterate:-

Originally Posted By Chris Battle
With the fork leg sliders extended all the way down, I can feel and see almost 1mm of play, when pushing and pulling, back and forth, from the bottom of the sliders. Would this be normal?

You're looking for "Yes" or "No". It doesn't exist. John and others have explained why "Yes" or "No" doesn't exist.

Regards,

#678033 - 12/17/16 8:16 am Re: Excessive Fork Play? [Re: Stuart]  
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Hillbilly bike Online content
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I can straddle the front wheel of a Triumph with by legs ,grab the bar and give a strong twisting motion. It all flexes quite a bit. I tried the same on an 80's Guzzi with 35mm forks and there was no flex...The flex I'm talking about is not from loose steering neck bearings.

I believe the flex is primarily caused by poor clamping of the yokes..And ,as JH says, the necessary loose slider clearances because of all this slop...
Despite all this flex the bikes do handle just fine...Makes you wonder, huh?
I modified a 39 mm fork assembly off a 90's Yamaha FRZ600 to fit my 70 T120..The bike didn't necessarily handle better but myself and other Triumph riders noticed it rode better and the front end felt better "planted"...


650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
#678041 - 12/17/16 9:00 am Re: Excessive Fork Play? [Re: Chris Battle]  
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Allan Gill Offline
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Rotherham - S. Yorkshire
Clamping the wheel between your legs and twisting for bars will reveal some twist on most bikes, maybe not so much with upside down forks. But loose play is where the problem begins and not actual flexing of the stanchions. In that instance there should be no sloppiness.


beerchug
#678070 - 12/17/16 2:31 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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John Healy Online content
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So here's what I would do to improve the situation.
1. Get a pair of 38 + diameter fork tubes that do not have tapered tops. Make sure the o.d. are ground to a tolerance of 0.001" for the length.
2. Get a pair of sturdy alloy triple trees where the bores are at perfectly right angles to the triple trees and the holes held parallel over a distance of 24" to a tolerance of + - 0.001".
3. redesign the axle situation where it is locked in one fork leg and left to self align in the other (Like Norton, Ceriani, and some BSA models.
4. Completely redesign the dampening system.

Or
1. Make sure the bushing clearance is as specified in the Workshop manual.
2. Correct as much as you can being sure the forks are free to move up and down without any binding. All this as your experience, access to tools and budget permits. Because the magic is every bit related to just how close the center line of the tubes is held.
For example: If the grooves in the axle don't center on the two studs in the lower member precisely when you offer the caps and tighten them they will pull in, or push out, the fork tubes. If if they are centered if you tighten both without bouncing the front end up and down to let every thing center itself before tightening the second cap you can force the legs out of alignment.
3. Do what other Triumph riders have done for years: Go ride your motorcycle.

Would someone else please take the time to explain the math here. And how the 1mm (0.040") movement will change from full extension to full compression. I have work to do...
John


#678129 - 12/17/16 10:48 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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Chris Battle Offline
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Coffs Harbour, NSW, Australia
Allan Gill: Thank you for your response to my question regarding detectable play in the front end of a bike. You have said:

"can't say that on the BSA or Triumph forks I ever found any disconcernable play when the front wheel was raised and the stanchions pulled back and forth."

I'm not familiar with your word "disconcernable", but I presume it means the same as discernable? In other words I think you are saying that you didn't detect any obvious play in those forks when performing your test. That is useful to know.

Les P: Thank you for your response to my report of almost 1mm of play that I detected when the fork leg was fully extended, and consequently the bushes were close together (separated only by the damping sleeve). Your contribution is that that amount of play, in that position, is to be normally expected.

Hillbilly bike: Yes I would expect these kinds of forks to flex like you have described.

To Brit Bikers in General: The three posters mentioned above have understood my question, as it was set out in the beginning of this thread, and have given helpful feedback.

This, being my first post in this forum, has not been without some unpleasantness. I have received what I have experienced as some unwarranted "flaming", as a reading of this thread shows, and I think the best I can do is to not read or respond to such posts in the future.

Cheers............CB.

#678163 - 12/18/16 8:59 am Re: Excessive Fork Play? [Re: Chris Battle]  
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I think you play is normal. A good check before doing any more is to fit the yokes/ triple trees , fit the fork legs and wheel / axle with the stanchions just short of the top yoke, now look through the top yoke stanchion holes, if everything is true then the stanchions will be Concentric with the top holes, if the bottom yoke is bent then one or both stanchions will not be Concentric with the mount holes. If you find misalignment then the bottom yoke must be bent ( assuming good true stanchions), the bottom yoke is relatively soft and easily bent, the bend is corrected by fitting an old stanchion to the bottom yoke and levering to bend straight, usually the yoke has been pushed back by a front end collision on the RHS.
Another sure sign the bottom yoke is bent, if, when all is fitted you have to " tweak " the handlebars to make them parallel to the wheel axle then you have a bent bottom yoke, a very common thing on old bikes. obviously if the yokes are not true then the forks will not stroke smoothly and will bind, one of the reasons for the loose tolerances on the slider bushes is to accommodate a small amount of misalignment.


71 Devimead A65 750
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The poster formerly known as Pod
#678185 - 12/18/16 1:25 pm Re: Excessive Fork Play? [Re: Chris Battle]  
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John Healy Online content
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Boston, Massachusetts
Chris
Forks binding will effect the handling much more than if they have proper clearnce. The video you posted on the Rat forum concerns me a lot more than a little more than standard clearance. Instead of a simple yes-no answer I tried to explain why and the folly of closing up the clearance with out explaining why it can be a fools errand.

By presenting the video you exposed that there was something behind your question. It was no longer about was the play normal, but you introduced a lot more to your question. I tried to explain why the so called "extra", as some feel, Triumph used up to 0.006" clearance on the bushing. Now even with this clearance the standard manufacturing tolerances and the design of this fork 0.006" clearance could be insufficient. This is why the race shop would selectively fit parts to suit.

You are working on a motorcycle you have no idea what it went through with previous owners.

I would add:
The axle could be bent.
One or both lower legs could be bent.
The center to center distance between the two annular grooves that locate the axle could cut in the wrong place pushing the fork legs inward or outward.
The triple trees could have been bent.
The taper at the top of the tubes could have been cut offset or at angle.
The fork tubes could be bent.
The fork tubes might not have been ground straight.
The taper in the top triple tree could have been cut offset or at an angle.

So to the video if you remove that 0.006" clearance you have just started the job! Now you have remove all of those thousandths of built up error from all of the parts that make up the front end.

I am sorry I didn't give you a yes or no answer, but after 50 years of doing this one thing I didn't see a yes or no question? Instead I tried to explain why and how! Knowing what
I know about Triumphfro t ends it scared me.
John


Last edited by John Healy; 12/18/16 1:32 pm.

#678337 - 12/19/16 6:49 pm Re: Excessive Fork Play? [Re: Chris Battle]  
Joined: Dec 2016
Posts: 17
Chris Battle Offline
BritBike Forum member
Chris Battle  Offline
BritBike Forum member

Joined: Dec 2016
Posts: 17
Coffs Harbour, NSW, Australia
John Healy: Yes, I now fully understand what you are saying regarding why Triumph set out that specific range of clearances in their front forks. Perhaps, as the old saying goes, I'm "trying to make a silk purse out of a sow's ear"?

It would be instructive if there was some feedback about how the minimal clearance forks in that video performed on a bike.

I have a question regarding the role of the axle in this equation. You have written:

"If the grooves in the axle don't center on the two studs in the lower member precisely when you offer the caps and tighten them they will pull in, or push out, the fork tubes. If if they are centered if you tighten both without bouncing the front end up and down to let every thing center itself before tightening the second cap you can force the legs out of alignment."

Are you saying not to have the axle sticking out more on one side of the bike than the other? What is the purpose of those grooves? It would seem to me that the last thing you would want to do is reduce metal where you want maximum strength.

Were you also saying that one side of the axle should be tightened on first, then the forks pumped up & down, prior to the tightening of the other end of the axle?

I may have to start another thread, because I have an issue with the steering head on my bike, but it is somewhat related to this subject of handling:

I installed tapered roller bearings to replace the standard cups, cones & ball bearings, but discovered that the top bearing race sits "proud" above the steering head of the frame by about 1.5mm. I read an earlier post on this forum where someone complained of this same issue, and a question was raised whether the increased height of the top yoke, which sits on the top bearing race, might affect the steering geometry and hence the handling of the bike. Any thoughts?

gavin eisler: Thank you for your tips. Looking down through the top yoke, the stanchions look "more or less" Concentric, that is to say that I think any attempt to make them perfectly Concentric, by bending the bottom yokes, would just shift them to another "more or less" Concentric position.

Les P: I kind of think that if forks were put together a bit on the tight side of clearances, that the bushes would soon wear-in, and the fork action would free up. I think that what you were saying.

Cheers all...........CB.

Last edited by Chris Battle; 12/19/16 7:35 pm. Reason: wrong measurement
#678340 - 12/19/16 7:05 pm Re: Excessive Fork Play? [Re: Chris Battle]  
Joined: Dec 2004
Posts: 8,891
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,891
Scotland
The top yoke being raised by 2.7mm will not affect the handling at all, the biggest issue will be the stanchion being exposed above the fork ears, black tape wrapped round the stanchion cures that.

On the alignment the best method is with all bolts and nuts including the mudguard stays loose starting at the bottom bounce and tighten the axle bolts, then bounce and tighten at the next set of bolts upwards, continue upwards until you tighten the fork top nuts. If the action gets tighter at any stage stop and investigate.

#678349 - 12/19/16 8:15 pm Re: Excessive Fork Play? [Re: Chris Battle]  
Joined: Mar 2005
Posts: 9,970
John Healy Online content
John Healy  Online Content


Joined: Mar 2005
Posts: 9,970
Boston, Massachusetts
Quote:
Are you saying not to have the axle sticking out more on one side of the bike than the other? What is the purpose of those grooves? It would seem to me that the last thing you would want to do is reduce metal where you want maximum strength.


OK... the studs affixed to the bottom of the lower fork legs that retain the axle via the axle caps are an important component when considering whether the forks will go up and down. The center to center distance from side to side is determined by several things.
a. the center to center distance between the holes that hold the fork tubes in the triple trees.
b. The positioning of the threaded holes in the fork legs themselves.

Every measured part on this motorcycle has a plus or minus tolerance to which they were made. In some cases one part is made to a plus tolerance and the matching part to a minus tolerance and they cancel each other out. But if both are made to a plus or to a minus you can run into problems. So what I am saying is the distance between the studs could be on the drawing. But they also could be less or more than the drawing and be acceptable (in this case we have clearance in the fork bushings to compensate).

So to with the two annular grooves in the axle IF the center to center distance between the center line of the studs is 6 inches and the center to center distance between the annular grooves on the axle is 6 1/64" (0.015") they will pull or push the tubes one way or the other and you are not going to have a fork that works. Now factory axles aren't perfect and after market ones "are catch as catch can." Some are OK, others rubbish.

Quote:
Were you also saying that one side of the axle should be tightened first, then the forks pumped up & down, prior to the tightening of the other end of the axle?


When you tighten one axle cap first, and bounce the front end up and down, it lets the lower legs center themselves before you tighten the axle cap. Some times you have to do it a couple of times.

My first thought when I sat through that video was Just because you can doesn't mean you should. You cannot look at getting the fork to work well "correcting" that one thing you think is wrong. Any apprentice with a lather can make bushings with less clearance. It takes someone used to working on these to understand why that clearance was there in the first place. The factory wasn't stupid. They were well aware that with the design, ability to hold tolerances at the price they had to do it too it wasn't possible to make a fork like ones fitted to modern motorcycles.

You might never turn it into a silk purse, but with some effort you certainly can turn it into a wool sock.


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