Halo tophased,
I hope I understand your problem correctly.
Just try to warm up with the fork with a hot air gun. When everything is hot, maybe you can push down the cap with a clamp.

Good luck, Karsten

Hallo tophased, hallo Georg

I wouldn´t beat on the top of the cap with a metal hammer, because it´s very easy to damage the chamfer, where the Oring sits.
Georg´s second proposal is much better, but you need a srew with, if I remember correctly, M7x1 thread.

Best regards, Karsten

Hi,

that's quite normal.
First loosen the upper srew of the fork bridge, just a bit, to make sure that there is no pressure around the tube.
Then use a tube or someting round and hollow that is smaller in diameter than the fork's tube. Put this on the cap and use it as a chisel.
You may use a real hammer for this, because there is nothing You can damage inside. As soon as the cap gets loose, You will feel the spring going down. May be You will have to press the cap down and let it come up again a couple of times, until the cap pops finally out of the tube.
When You have let the air pressure out of the fork (!), and there are the original, weak, flat springs inside it, You don't have to fear much. The cap won't pop out for more than two inches.

Cheers,

Stefan

thanks guys
ended up spraying half can of Loctite freeze and release lubricant on to the cap
while using a bike (air) hand pump and to crease the pressure in the fork ( i had to change the seals too)
a couple of little taps on the cap with a socket and hammer . that worked
the cap shot across the garage  like a rocket taking out a set of works lights !
except now the air valve on the cap is trashed !!
oh well at least it came out !!

hi Stefan thanks for your concern
but don't worry
I used a bicycle  hand pump not an air compressor !!

Hello Evripidis,
I guess you want to remove the Cap to take out the springs inside of the fork-tube?

If it is so, remove the Steering bar to get enough space. Be careful , so that no Brake fluid escapes from the reservoir and perhaps damage other parts, e.g. your Fuel-Tank.

To remove the Caps it self you will need
 - a small Screwdriver with blade end, /(for slotted screws),
 - a Wrench Nut which fits to the Air Valve hex, and a suitable tool to get more distance for better workspace.
1. Take the wrench Nut assembly onto the hexagon socket of the air Valve
2. Puch down the Cap, enough so that the circlip inside is fully visible.
3. with the Screwdriver you can level out the beginning of the circlip. But be aware that the circlip is not jumping away. It it difficult to find it.
   It is a little bit tricky, but it will coming out.
4. Now let the plug (Cap) coming out by releasing pressure. If the Plug is not coming out at the first time, try again to push the plug into the Fork Tube and than release the pressure of holding down immediately. If necessary try it several times.
Reason could be some dirt inside, or a little bit of deformation of the grove of the circlip.

Regards Anja

Hello Evripidis,
one  at first. My Description belongs to the removing of the Fork-Tube-Caps (Imags No: 15/38) with the Air valve in it.

Do you want to change the Oil seals of the Fork?
If you want to go ahead with your scheduled Replacement, be aware not to scratch the inner Tube !!!

Primary, it would be better to take the Front Fork Units out and fix them on your bench.

I have attached to images with parts of the Fork Assembly:
8 /31 = Dust Cover
4/27 = Circlip of the Oil-Seal
3/26 = Oil-Seal

Regards Anja

Hello  Evripidis,
you need to support the Engine !
-----
have a Look here:
https://www.tr1.de/pages/forum.php?iQuery=num=1724322130/3&anchor=3

Re: Zylinderköpfe demontieren an der Yamaha xv1000 tr1 5a8
Antworten #3 - 26.08.24 um 10:42:34
including a drawing for a selfmade Enginesupport (german: Motorstütze)
see also the pictures one abow
-----
You can use it for:
when using two additional clamping wedges to lift it a little bit (until the the Front Tire has cleard the ground):
- for Front Tire change
- for Works on Front Fork

without wedges:
a) loose Front Fork Clamps a allow Fork Tube to slip up, the Engine support device has to be come to the Ground.
Then:
- for Works on the Engine. e.G. for removing Cylinderhead / Cylinders

IF you are support your Engine by using a Wood Block or a hydraulic lifter, be aware to secure this safely to prevent falling away your Support from the Engine.

While working on the Front Fork, taking out a Tube or so, it is possible that your bike can come to a swinging. This swinging can shake your support away, if it is not fixed in position.

regards Anja

Hallo Anja,

I did it differently! But your plans are spot on and will at some point implement them.

I drilled 2 holes in the ground and attached a hook. The I used a ratchet strap to tie down the rear end very lightly. I had enough clearance to remove the forks.

Now I am back to read again what you have written about removing the cap....

I might have a hard time.

I think that the forks where filled with the wrong oil, it was too thick coming out....

Evros

Good Moning Evripidis,
your TR1 looks good, so far.
You are very creative, indeed.

Fork-Oil : 10W , Volume per Tube: 288ccm
Kind regards
Anja

Have a look:
https://www.tr1.de/pages/technics_manual.php?key=XV750se&lng=eng&flg=0&pge=2032
Regards Anja

XV750 and TR1 have different forks. The first is a 36mm diameter and the latter a 37mm fork. Also, if you're able to feel the difference of 14ml fluid, you should probably NOT ride a TR1, but apply for a motorcycle road racing series.

Also depending on your weight and whether you plan to use the air-assist or not, you may want to add even more oil as well.

(I've run XS1100 forks in my TR1 for close to a decade now, so I am not sure how much oil I used to use in my TR1 forks, but I think somewhere in the ballpark of 15 percent extra oil.)

Cheers,
Greg

Not entirely sure, which number you're referring to, but regardless of which, I think you're due for an extra Baklava after lunch just to make sure you don't get blown off the bike.  

Minimum 290 ccm per fork leg. https://www.tr1.de/cgi-bin/yabb2/YaBB.pl?num=1628266373