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Falcon 67 front forks

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Falcon 67 front forks

Post  IAFalcon67 on Sun Jul 24, 2016 8:11 am

Does anyone have a picture of their dismantled front forks (Falcon 67 or equivalent) that I can have a look at?

I have some play in my front forks and I am wondering whether the slider bushes are worn. The manual makes it sound rather complicated as the 'bushes in the tube assembly are line reared' after being fitted.

I was going to take them apart to have a look in case I can rotate the bush instead of replacing it.

Has anyone done this before - and if so, what should a novice like myself look out for?

THANK YOU!

IAFalcon67

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fork bushes

Post  piston 197 on Sun Jul 24, 2016 8:40 am

I have done this repair abot 2 dozen times, but no longer have the machinery available to do it, the bushes are held in by the oil nipples and a friction fit, new bushes can be made from Tufnol, they are made about .005" undersize , fitted and then line reamed as the forks are never straight.
The club had a reaming tool ex factory that was loaned out to members for use, but unfortunately the last custodian died suddenly and it was lost. It is an expanding reamer with pilot ends of about 18" long, so that one end is located before the reamer cuts the second bush.
Turning the bushes will be no use as the play will be just in a different direction.
It is only usually the bushes in the bottom of the fork that wear.
I used to re-tube the sliders with oversize 1.125 hydraulic tube and ream the existing bushes out to suit if wear was not excessive, original tube size on the falcon was 1.120" and on earlier models 1.096"
Bantam John ( Sheffield classic Motorcycles did have some new bushes, or if stuck I have a serviceable set of forks from a falcon 67

JH
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piston 197
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Re: Falcon 67 front forks

Post  IAFalcon67 on Sun Jul 24, 2016 8:58 am

Wow!A very comprehensive response, thank you so much! It sounds like it might be really difficult unassisted so I will pop around to a friend tomorrow and show him your reply.

It's a great comfort to know you have some forks though, I may end up doing that!

THANK YOU!

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Re: Falcon 67 front forks

Post  IAFalcon67 on Mon Jul 25, 2016 7:24 pm

How do I get the bushes out!? Embarassed

IAFalcon67

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Bush removal

Post  piston 197 on Mon Jul 25, 2016 7:28 pm

Remove the oil nipples get a piece of about 3 Ft long 1 1/4" diameter bar, turn a pilot of about 1" long and about 1.120" diameter, insert from the top of the forks, locate the pilot in the upper bush and hammer them both out downwards, the pilot supports the bush and prevents the bar crushing the bushes
SIMPLES
JH
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Re: Falcon 67 front forks

Post  IAFalcon67 on Mon Jul 25, 2016 7:36 pm

piston 197 wrote:Remove the oil nipples get a piece of about 3 Ft long 1 1/4" diameter bar, turn a pilot of about 1" long and about 1.120" diameter, insert from the top of the forks, locate the pilot in the upper bush and hammer them both out downwards, the pilot supports the bush and prevents the bar crushing the bushes
SIMPLES
JH

Thank you. When you say turn a pilot - is that the same thing as a bit of wood chiselled down so that the first half goes in the bush at a tight fit and the rest is out of it?

I am wondering whether I might swap the top and the bottom bushes around? line reaming is something I haven't ever heard of, let along done so I was wondering whether I might get 500 miles or so out of swapping them while I got my head around doing it properly!?

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Bush removal

Post  piston 197 on Mon Jul 25, 2016 7:43 pm

Hmmmm!, bits of wood, turning bushes around, swapping them over, maybe I was spoilt with an engineering apprenticeship and a career in engineering, I can see the merits of your suggestion if you were stuck on the roadside in the wilderness, but if you are going to do it , do it properly, and if you lack the knowledge or ability, take it to your nearest engineering workshop and get it done properly, it will be worth it in the long run ?
JH
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Re: Falcon 67 front forks

Post  IAFalcon67 on Mon Jul 25, 2016 7:49 pm

piston 197 wrote:Hmmmm!, bits of wood, turning bushes around, swapping them over, maybe I was spoilt with an engineering apprenticeship and a career in engineering, I can see the merits of your suggestion if you were stuck on the roadside in the wilderness, but if you are going to do it , do it properly, and if you lack the knowledge or ability, take it to your nearest engineering workshop and get it done properly, it will be worth it in the long run ?
JH

It sounds as though I am getting confused with the technical language so I will show your message to a friend of mine and get him to show me what to do! I am very keen to learn to do it myself. I am hoping to do a little trip on it in a few weeks which is why I was thinking of swapping them over until I worked out how and what I needed to do it properly! The bantam front forks were so much easier!

Thanks for your help!

IAFalcon67

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technical terms

Post  piston 197 on Mon Jul 25, 2016 8:10 pm

Pilot , a short piece of a sliding fit into the internal diameter of the bush, same diameter as the sliding part of the fork, this gives a location inside the bush while the bigger diameter, just slightly smaller than the inside of the top part of the fork, bears down on the bush while the "pilot" diameter supports the bush from being crushed when being drifted ( hit)

Line reaming, a reamer is a hand driven cutting tool, for line reaming it has to be long enough to cut both bushes at the same time to ensure they are in line to compensate for any bend in the fork tube, It can be a shorter adjustable reamer, but must have a pilot diameter to support it in one bush while cutting the other if the reamer is not long enough to cut both bushes at once
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Fork Springs

Post  IAFalcon67 on Thu Jul 28, 2016 2:51 pm

everything is going very well so far. I have had a good look at the forks and there is a reasonable amount of pitting so I am going to see whether the local chrome fork company can re-chrome them for me. which leads me to my next title....

How do I get the springs out?!

IAFalcon67

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spring removal

Post  piston 197 on Thu Jul 28, 2016 3:10 pm

In the top of the fork leg under the top yoke ( you have to remove the top yoke) there is a cup held with 2 horizontal bolts that go through the side of the top yoke and the top of the legs, remove these and there is a central screw in the cup, undo this and the bottom sliders will come out with the springs attached.
To get the springs off the bottom legs, once removed , find the end of the spring and using a drift ( alloy bar is ideal) tap the springs anti clockwise with a hammer whilst holding the legs in a vice or similar to prevent them turning, if you try to unwind the springs they will just tighten themselves on the leg.

JH
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Re: Falcon 67 front forks

Post  IAFalcon67 on Sun Aug 07, 2016 7:03 am

Thank you for all you assistance, the job is nearly done.  I wasn't able to get the springs out of the stanchions. I was concerned about spoiling the fitting IN the stanchion for the spring.  The Chrome platers said they couldn't do the job with the sting it, so I will have do with what I have. The stanchions are pitted so it is not ideal but OK for now.

l but I have sanded the stanchions very down carefully to remove any burrs which I hope will prolong the life.

I think I have a bit left over which is a bit awkward. Definitely not from the forks, but it is a sort of rubber oil seal I suppose. The only other thing I took off was the head stem helmet nut and fork top plate. Any ideas as to where to look would be great as my diagrams don't seem to cover all that.

It wasn't a bad job as I didn't have any of the tools and I had to make do.  I think the bearings in the head stem need some attention but I will wait until I can get a second opinion.

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spring removal

Post  piston 197 on Sun Aug 07, 2016 7:14 am

The spring removal is simple, just grip the stanchions in a vice, find the end of the spring, using a piece of aluminium or copper drift ( something soft) locate the drift on the last coil end and tap anti clockwise to remove spring, if you try and turn the spring manually it will just tighten itself and grip the thread on the stanchions harder, but will tap off easily, no damage will be done.
The only seals on the forks are the 2 seals one on each leg on the end of the fork tubes to prevent oil running out into the rubber bellows.
The seal is a Payen part X149, no longer available , but does turn u at auto jumbles , look for small orange Payen box with No X149 on end
Rubber bellows can be sourced from motor suppliers I have used Girling part No TBR1000 in the past, which is a universal gaiter kit for front wheel drive cars, they come with 3 different sizes on each end, and have to be cut to leave the required size on each end for the purpose they are used for .
JH
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Re: Falcon 67 front forks

Post  IAFalcon67 on Sun Aug 07, 2016 7:28 am

Thank you for the tip on the springs, I did try when you said about it before, and asked a friend to give me a hand with it as it was all rather stubborn. After talking to someone else who knows about these things about the difficulty I was having, they said they managed to snap some off so I am erring on the side of caution for now and they remain as they are.

I replaced the two seals on the bottom of the folks with replacements from Bantam John (who also had the bushes).

I have some new bellows back where I live which came from a Triumph which I will put on when I get back; they may not fit so I will certainly remember the Girling tip. Thank you.

The rubber seal i have left over may well have been on the workbench already - or put there by another user! I hope that's the case anyway.

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springs

Post  piston 197 on Sun Aug 07, 2016 7:32 am

Over the years I must have removed dozens of springs this way and never snapped one off yet, can only think the "friend" who snapped one off was either unlucky,brutal or maybe the spring was already cracked ?
JH
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Spring removal

Post  IAFalcon67 on Sun Aug 07, 2016 7:48 am

piston 197 wrote:Over the years I must have removed dozens of springs this way and never snapped one off yet, can only think the "friend" who snapped one off was either unlucky,brutal or maybe the spring was already cracked ?
JH
No, I don't think it was down to incompetence but may have been bad luck (which I am too familiar with!).  I wasn't doubting your methodology, I did thank you for your help, and the method has been noted for when I get home.  I don't want to end up with a bit of bad luck and an unusable fork, so I am erring on the side of caution for now which is the best way of caring for this old girl.  I haven't done things the same way as you, but I have managed to get the job done and I am grateful to your help. Thank you.

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Re: Falcon 67 front forks

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