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Fork cap nut thread issues

9.4K views 27 replies 11 participants last post by  GrandPaulZ  
#1 ·
I am rebuilding a TR6 which is a mixture of late 69 early 70. The forks were in bits but there are a lot of new parts.
Here is the problem. The fork top cap nut and damper bottom nut do not fit the stanchions.
The stanchions are new and numbered 4007 which should be correct. I bought a pair of top nuts no 4258 and they dont fit either so my thoughts are that the stanchions which were presumably bought by the previous owner as replacement are wrong and for a later model. I have a 1964 A65 with later forks and conical hub fitted and the top nuts for that fit the new stanchions but unfortunately I dont know the year of the forks.
Did the top thread change during the production run and if so what is the part no of the top nuts and damper nuts to fit the later models
 
#2 ·
Welcome to the Forum


I suspect you have a mixture of part as 97-4007 tubes are 1971/72 OIF fork tubes. Top cap nuts (97-2245) and bottom nuts (97-2091) are the same from 1968- thru 1970 MODEL years. Fork tubes 1698/1969 (97-2092) and 1970 (97-3904) are essentially the same and can be interchanged in pairs.
It might help if you can post a few pictures of what you have there and a partial VIN of engine and frame (if different) so it can be determined what you really have there.


K
 
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#3 ·
Hi John,

Echoing and amplifying "Kadutz's" post:-

Stanchions [97-]4007 are for conical hub forks ('71-early '73).

I bought a pair of top nuts no 4258 and they dont fit either
Well, they were also originally conical-hub so they should. Couple of things you should be aware of:-

. '71-early '73 and pre-'71 threads are very similar (28 tpi - threads per inch - and 26 tpi respectively) so dealers who don't take a bit of care screw up regularly.

. Modern female threads (e.g. in stanchions) are regularly undersize, and modern male threads (e.g. on fork top cap nuts and damper bottom nuts) are regularly oversize, from dealers who don't take a bit of care ...

If you have thread gauges and a micrometer or callipers, you can check for the aforementioned faults yourself. If not but you know a local one-man-band machinist or engineer, he can check. If still not, you need to find one. :)

Fwiw, that the top nuts from from your A65's later forks fit your [97-]4007 stanchions suggests the top (and bottom) nuts you had with the project already could be the wrong thread, the "4258" top nuts you bought could oversize. :(

If you haven't come across this sort of problem before, ime 'fraid it's regular; :( I've done my own 'quality assurance' for several years, acquiring the likes of thread gauges and a micrometer or callipers isn't expensive.

what is the part no of the top nuts and damper nuts to fit the later models
When you get new correct 97-/H3904 or 97-/H2092 stanchions, be aware the '71-on [97-]4258 top nuts (and damper bottom nuts) are more likely to fit; ime, the '71-early '73 28 tpi thread is being used on pre-'71 stanchions, even though the pre-'71 fork top cap nuts and damper bottom nuts are still available.

Also, before you start assembling the new fork parts, ime check diameters and clearances or particularly stanchions, sliders and bushes with the figures in the General Data section of the pre-'71 650 workshop manual. Some modern parts makers are somewhat ... errr ... lax ... about such fripperies. :cool:

Hth.

Regards,
 
#6 ·
According to the 1971 parts book the stanchions are 4007 and the nuts are 4258. The stanchions are numberd 4007 but hand written not a Triiumph part no sticker and the nuts are not numbered. As these dont match I am trying to find out which is numbered incorrectly.
It is an oif model but the frame and engine number do not match and it seems it is a collection of parts from approx the same year.
My question remains though. What year did the threads change and what did the part number change to.
It would appear from another answer that it may not be as simple as getting the correct part numbers but also that some pattern parts are incorrect.
It may be best buying new stanchions and nuts from one dealer but this would be a waste of the new stanchions that came with it
 
#10 · (Edited)
Hi John,

It is an oif model but the frame and engine number do not match and it seems it is a collection of parts from approx the same year.
In your first post is, "I am rebuilding a TR6 which is a mixture of late 69 early 70." "oif" stands for 'oil in frame"; no Triumph was "oif" before the 1971 model year. So how did you arrive at "a mixture of late 69 early 70"?

According to the 1971 parts book the stanchions are 4007 and the nuts are 4258. The stanchions are numberd 4007 but hand written not a Triiumph part no sticker and the nuts are not numbered.
:confused: Why would you look in a 1971 parts book when you are, "rebuilding a TR6 which is a mixture of late 69 early 70"? And, given the parts you're talking about are supposed to fit a motorcycle nearly fifty years old, why would you expect "a Triiumph part no sticker"? Fwiw, parts made when the motorcycle was new didn't have "a Triiumph part no sticker" ...

As these dont match I am trying to find out which is numbered incorrectly.
I have posted already for you how to find that out. And neither might be "numbered incorrectly", one or both parts might simply be over- or under-size. I told you how to find that out too.

It may be best buying new stanchions and nuts from one dealer but this would be a waste of the new stanchions that came with it
:confused: As advised already, why would you not simply find someone to measure the threads and diameters of the parts you have? By definition, in front of you, you have a computer with the internet. You also have the Yellow Pages. You also have garages near you that, if they don't service motorcycles, they service cars; if they aren't capable of fixing the threads they fcuk, the service/workshop manager (franchised dealer) or owner (non-franchised) knows the aforementioned local machinist or engineer who does for them.

When considering buying more new stanchions and nuts, bear in mind dealers buy from wholesalers; there are but three(?) wholesalers supplying Meriden Triumph parts dealers all over the world; in order that they make any profit at all, one wholesaler rarely if ever commissions a batch of parts that another wholesaler is already supplying. So, if the problem is simply that stanchions are undersize and/or nuts are oversize, you'll simply be buying more parts that don't fit together?

My question remains though. What year did the threads change and what did the part number change to.
I answered that in my previous post.

The BSA nuts that fit came from a set of oif forks with conical hub as well but as it is an early model with later forks it doesn't help with dating
Errrm ... not intending to appear harsh but ... you appear to keep having problems with what's posted on this website:-

. If your BSA has "oif forks with conical hub", it absolutely dates the fork top nuts. I've already posted the information for you.

. You posted incorrectly in two forums before starting this thread here, because you failed either to read or to understand what's written by each forum's title.

. The people that post information answering questions like yours volunteer their time and knowledge. The people that take the time to post directing you to the correct forum volunteer their time. The moderators that delete your threads from the wrong forums volunteer their time. Whether intentionally or not, you're rather taking the piss constantly not reading/understanding what's been posted, posting incorrect information, asking questions you've had answered already and failing to follow simple advice you've been given.

"Kadutz" has suggested you should post pictures of what you're working with. I agree, plus frame and engine numbers. Plus take time to re-read what's been posted for you already.

Hth.

Regards,
 
#9 ·
Probably easier to head to an autojumble or bricks and mortar seller with the bits and see what they say
Obviously throwing the top nuts and sourcing whatever fits is cheaper than the other way around
Pictures really help, Afaik the early OIF bikes had tapered stanchions? Then they were straight?
 
#14 ·
Hi John,

Just checked the numbers and it is a 1970 engine and a 1972 frame. Don't know where I got 1970 from.
:Darn ...

Assuming you are fitting conical-hub forks into conical-hub yokes on the frame:-

The fork top cap nut and damper bottom nut do not fit the stanchions.
The stanchions are new and numbered 4007
I have a 1964 A65 with later forks and conical hub fitted and the top nuts for that fit the new stanchions but unfortunately I dont know the year of the forks.
Doesn't matter. As I hope you've realised by now:-

. all conical fork top nuts are interchangeable;

. if the stanchions are "numbered 4007", why would they be "wrong", particularly as top nuts from your other bike's conical forks fit? :confused:

1970 engine and a 1972 frame.
You are aware that Triumph made substantial changes to the rocker-boxes for '71 to install the Triumph engine in the oil-in-frame?

Hth.

Regards,
 
#12 ·
Looking at various suppliers, the 97-4007 stanchions ('71-'73) should have 97-4008 top nuts, which seems logical to me.
These top nuts have flat tops with no recess for a sticker.
This applies to BSA and Triumph 650's with conical hubs.
 
#13 · (Edited)
Hi John,

Looking at various suppliers,
This applies to BSA and Triumph 650's with conical hubs.
A more-comprehensive search finds the following:-

. Searching eBay for 97-4008, 97-4258 or 97-4309 (see below), returned listings contain at least two, and often all three, part numbers.

. Entering any of those three part numbers plus "triumph" into an internet search engine, returned images are of either the same or very similar parts.

. Of '71 Triumph T150, 650 and 250 parts books, the first two list H4258, the 250 book lists H4008. The BSA Rocket 3 book lists 97-4258, the 650 and 250 books list 97-4008.

. '72, the T150 book lists H4309, the Triumph 650 book lists H4258, the Rocket 3 book lists 97-4309, the 650 book lists 97-4258.

. The part common to all of those is stanchion 97-/H4007.

. 73, the only parts books actually listing conical hub forks and brake are X75 Hurricane, T150 Series 1, "BSA T65" (BSA-badged Triumph TR6) and TR5T; all except the TR5T book list 97-/H4309, TR5T book lists H4258; stanchion on the T150 and T65 is H4007 (X75 and TR5T stanchions are different part numbers because they're longer).

. '74, the TR5T lists the same H4309 top cap nut (and H4455 stanchion) as '73.

The above is true of parts books on http://vintagebikemagazine.com/links/parts-books/, https://partsbooks.britishonly.com/ and Kim The CD Man DVD's.

Hth.

Regards,
 
#15 ·
Further revelations re. top nut, by supplier.
Draganfly: only list these for BSA's, 97-4008 flat top chrome plated.
Grin Triumph: 97-4008 flat chrome plated and 97-4258 flat SS.
TMS: 97-4008 flat, chrome plated and 97-4258 recessed zinc plated.
Burton (Brit bike bits) 97-4008 flat
Tri-cor: 97-4258 zinc plated, 97-4258/S SS and 97-4258/71, '71 only.
Hawkshaw: 97-4258C = 97-4008 chrome plated.

Some others were domed, chrome plated.

Summing up: it looks as if the original Triumph top nuts were flat-topped and zinc plated, because there are no stickers in the spares list.
Then chrome plated and stainless types became available and the chrome plated type were already available as BSA 97-4008.
I suspect that somewhen during or after 1972 the recessed type with sticker arrived in zinc plate, followed by chrome plate, plus SS.
All of these fit the 97-4007 stanchions.
But this could be cobblers!
 
#16 ·
Thanks for all the assistance but it only seems to have complicated things without providing an answer.
According to the parts book I have for TR6 1971 the stanchion is 4007 and the top nut is 4258. I bought some 4258 nuts and they do not fit.
While all sorts of models give stanchions as 4007 it is clear that the thread is not the same for all years of the conical hub forks because the original nuts do not fit yet the ones from the BSA do fit
The BSA ones are flat topped and the Triumph ones that dont fit (the ones that came with the forks) are the ones with a recess in the top. This sems to be a variation between models though so shouldnt be a problem if the stanchion number is the same.
The top and bottom nuts that came with the forks are the same thread as each other but the BSA nuts that fit are a slightly different pitch so it seems likely that the thread changed somewhere in the production run. This is what I am trying to find out. I bought the forks in bits and am considering the possibility that the problem may be down to the quality of pattern parts but this again is only a guess.
Even if the new 4258 nuts I bought were poor quality pattern parts then surely they should still have been the same pitch as the BSA ones.
 
#22 · (Edited by Moderator)
John,

The top and bottom nuts that came with the forks are the same thread as each other but the BSA nuts that fit are a slightly different pitch

While all sorts of models give stanchions as 4007 it is clear that the thread is not the same for all years of the conical hub forks because the original nuts do not fit yet the ones from the BSA do fit
One thing in this thread is certainly very, very clear, but it is absolutely not "that the thread is not the same for all years of the conical hub forks"...

The very fact that you can take the nuts from the conical hub forks on your BSA and fit them in your other stanchions would've demonstrated several posts ago to anyone else that it is the "nuts that don't fit" that are the problem.

THE reason they "don't fit" is precisely because they are "a slightly different pitch" from the thread in the stanchions.

Because (almost) everyone who's been advising you knows the thread ABSOLUTELY DID NOT "change somewhere in the production run", the "slightly different pitch" shows "The top and bottom nuts that came with the forks" are pre-'71. This was written down for you all the way back in post #3.

the problem may be down to the quality of pattern parts but this again is only a guess.
Even if the new 4258 nuts I bought were poor quality pattern parts then surely they should still have been the same pitch as the BSA ones.
As is now usual, your "guess" is completely and entirely wrong. Ordinarily I'd blame whoever supplied you for the mistake of supplying pre-'71 top nuts instead of conical hub top nuts but, realistically, you've screwed up that many times ...

After reading all the previous answers I have just looked on ebay and find a number of sellers listing 4008 and 4258 nuts as the same thing (or interchangeable) but they all list them as up to 1972
Yet again you have not either read or understood what someone has given up their time to check and write down for you:-

. On its own, a single source of information - whether eBay sellers or parts books - is not always reliable. That is why I posted several sources of information. So you don't draw incorrect conclusions using only one source of information.

did the thread change in 73.
. If you look at the listed '73 parts books, you will see the conical-hub stanchions remained 97-/H4007. Restating what would've been blindingly-feckin'-obvious to anyone else by now, the threads in 97-/H4007 stanchions never changed.

Another previous answer contradicts that as it gives the 1973 TR6 as having 4007 stanchions and 4258 nuts. Same as 71 and 72
. This is absolutely correct. What contradiction?

It seems likely that the thread did change at some point
.NO. IT. DID. NOT.

One of the previous replies cast doubts on the stanchions being numbered incorrectly, but if all the parts I have and have bought are as numbered then they would fit each other. As they don't why is it hard to understand that one part at least is possibly numbered incorrectly?
As as been explained in the light of your revelations in your post 2003243978, the nuts you started out with have the wrong thread and the "4258" nuts you bought either also have the wrong thread or are incorrectly numbered. The only components that are for almost-certain numbered correctly are the stanchions numbered "4007".

Lots of forums seem to be a place for arguement. I am not looking for critics,I am looking for help and advice.
In all, between your threads in the wrong forums and the posts to this thread, you've been given at least twenty posts-worth of help and advice. The only person arguing is you, when you completely fail to read, understand and act on any of the help and advice given ...

Regards,
 
#17 ·
Yes I was aware of the engine changes, thanks. The engine came with most of the top end missing so this can be sorted as I collect he needed parts. It could prove to be a bigger problem than I expected though as the first assembly I started with was the forks and already I am finding problems with parts that should match but don't.
I bought parts books from a couple of years hoping to cross referance the parts I needed but already I am finding that is not working as parts I have bought which should fit don't. Unfortunately this doesn't tell me which parts are right and which are wrong.
I am starting to think I have bought a pile of mismatched parts from a project the previous owner had abanded due to nothing matching.
Good job it was bought cheaply. I am considering selling all the bits seperately on Ebay and giving up on it
I am also rebuilding a pre unit Bonnie and at least with that everything I have bought was what it should have been and fitted OK.
 
#19 · (Edited)
Another thought, John, is that the parts you've bought which should fit but don't, may have been incorrectly selected by the Parts Dealer.


For example, I purchased some stainless steel 2BA screws from my Nuts & Bolts lady only to find out later they weren't 2BA.
I even tendered a zinc plated 2BA screw to help her to confirm that she was supplying me the correct parts.
They even had a UNF/UNC nut and bolt testing board which she failed to use.

Luckily I didn't force these screws otherwise my parts would have been damaged.
 
#18 ·
After reading all the previous answers I have just looked on ebay and find a number of sellers listing 4008 and 4258 nuts as the same thing (or interchangeable) but they all list them as up to 1972 so did the thread change in 73. Another previous answer contradicts that as it gives the 1973 TR6 as having 4007 stanchions and 4258 nuts. Same as 71 and 72
It seems likely that the thread did change at some point so does anyone know the tpi of the various years and at least that way I can figure out what the parts are that I have.
One of the previous replies cast doubts on the stanchions being numbered incorrectly, but if all the parts I have and have bought are as numbered then they would fit each other. As they don't why is it hard to understand that one part at least is possibly numbered incorrectly?
Lots of forums seem to be a place for arguement. I am not looking for critics,I am looking for help and advice. Thanks
 
#20 ·
Lots of forums seem to be a place for arguement. I am not looking for critics,I am looking for help and advice. Thanks
My friend


I am not (nor are others) looking to be a critic or argue with you. In fact I have made no additional comments since the picture request. BUT it is impossible to be of valid assistance when the original information given is not correct.


Best of luck to you


K
 
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#21 ·
Firstly, I doubt if your stanchions are 97-4007.
And, yes everything changed in 1973 season, because the frame changed to T140 type, with a disc brake not a conical hub.
All 650's from 1973 to 1975 seasons were T140 frames with 650 engines, but there may have been an overlap in early '73, calendar year.
These were troubled times.
Been there, done that for my '74 T120V.
In '73 the stanchions became 97-4380 and the top nut to 97-4395, but that is not the end of the story.
The top nut now screws into a cap screw 97-4387, which is fastened by an allen key, into the stanchion.
The top nut does not screw into the stanchion, and now has a recess for the 190cc sticker 97-4259.

Secondly, I would avoid ebay cowboys, buy from reputable suppliers. Yes, I know some have ebay shops.
Thirdly, buy a set of thread gauges, then its possible to figure out the the thread type from the diameter and pitch.
 
#23 · (Edited by Moderator)
Caulky,

Firstly, I doubt if your stanchions are 97-4007.
And, yes everything changed in 1973 season, because the frame changed to T140 type, with a disc brake not a conical hub.
All 650's from 1973 to 1975 seasons were T140 frames with 650 engines, but there may have been an overlap in early '73, calendar year.
Afaik, you're one of only two people who could read this thread and confuse John The OP even more ... while missing the bleeding obvious ...

Why would the stanchions not be 97-4007? John has posted that he can take the top nuts from the conical-hub stanchions on his BSA and fit them in his project's stanchions. It's conceivable that his project's stanchions could be X75 or TR5T but, given one thing not in this thread is his project's stanchions are a different length, what would be the reason for that conclusion?

What "changed in 1973 season"? Apart from the (front) "disc brake" is absolutely nothing to do with the frame, only the forks - the oif steering bearings are exactly the same in 1971 and 1982 - at least 500 650's were built at the beginning of the '73 season with conical hub forks - 97-4007 stanchions and 97-4258 top nuts. These are not the same as '74 T120V's, which have disc-brake front ends.

In '73 the stanchions became 97-4380 and the top nut to 97-4395,
The top nut now screws into a cap screw 97-4387, which is fastened by an allen key, into the stanchion.
These are the disc-brake forks parts. As you should know from your "'74 T120V", the stanchions are not conical, therefore how is any of it relevant?

avoid ebay cowboys, buy from reputable suppliers. Yes, I know some have ebay shops.
The isn't any suggestion that John should buy from "ebay cowboys"; eBay references were used merely to show your previous post about 97-4008 was confusing; that and the "4258" that John was using are interchangeable.

At best, John The OP is badly-confused already. If you're going to post, could you make it something that doesn't also need corrections?

Regards,
 
#24 ·
Stuart ; nice one ! - your post number 22 made me smile - i was wondering when the "confusion" would create some upper case responses ! ---- like you say the stanchions are correct ; so if the nuts dont fit then they are wrong - simples
 
#25 ·
"the stanchions are not conical, therefore how is any of it relevant?"

Because John asked "so did the thread change in 73."
So, I replied.
Given the amount of mods that others have done to their bikes, he could have any stanchions.
 
#26 · (Edited by Moderator)
Caulky,

You have quoted out of context and ignored information the OP has posted, to try and justify posting irrelevant replies.

This entire thread has been about conical-hub stanchions and parts that attach to them. Anyone who doesn't understand that by now is off-topic.

Conical-hub parts fitted to motorcycles built at Meriden at the beginning of the '73 season are exactly the same as conical-hub parts fitted to motorcycles built at Meriden in the '71 and '72 seasons. Anyone who thinks disc-brake parts have any relevance whatsoever to this thread is mistaken.

"the stanchions are not conical, therefore how is any of it relevant?"
These are the disc-brake forks parts. As you should know from your "'74 T120V", the stanchions are not conical, therefore how is any of it relevant?
John asked "so did the thread change in 73."
So, I replied.
I have just looked on ebay and find a number of sellers listing 4008 and 4258 nuts as the same thing (or interchangeable) but they all list them as up to 1972 so did the thread change in 73.
Given the amount of mods that others have done to their bikes, he could have any stanchions.
I have a 1964 A65 with later forks and conical hub fitted and the top nuts for that fit the new stanchions
 
#28 ·
I believe this question has received MORE THAN AMPLE technical advice, discussion and correction, and that the OP should simply follow the crystal-clear advice provided and get along with it.

I'm closing this thread to eliminate any further frayed nerves.
 
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