F900 SL, Super Fatty Ultra DL,

[Jim76]

Hello there from the UK, Ive just stumbled across this site after searching for some info and hope someone can advise. Last week I bought a used F900 SL , white/slight beige in colour, with an oil leak; the air cylinder appears to be holding pressure thou. I think its the Super fatty ultra DL Headshock fitted. Ive been searching the web all day about how to replace the seals ect and to familiarise myself with these forks, and I think I may have a major issue. The aluminium nut at the top of the fork, which ive read is pressed onto the damper stem, is not attached to this stem ! The stem dont look broken atall its just that the ali nut is not attached to it, when I unscrew the round cap I can pull it right up and out ! Anyone know if this is repairable or does hat mean its for the knackers yard ? Also Ive read that because the damper cylinder is black in colour its not maintainable and I wont be able to get any seals, is this true ?

Im in a bit of a dilemma now, I really like the look of this old bike but im not sure if I can get hold of a replacement damper cylinder for it, or alternatively if I can install a more modern damper cylinder. Can someone help !!

Thanks, great site this and thanks for any info it will be real helpfull.

 

[MikeA]

You are correct, that hex is a press fit to the lockout shaft. In theory, you could repair it by removing the shaft and dimpling it with a center punch to restore a press fit, similar to knurling it. Practically though, it's probably better to replace it.

Does it say "super" on it? An Ultra DL with a black cartridge should be a 2000 to maybe 2003 70mm fork. It was a good fork and is definitely serviceable. Seal kit is part#HD166. However, there are special tools required to do a complete job, and they aren't cheap.

The only cartridges that would fit in that telescope would be another DL70 or an FT70 from a 1998 or 99 SL fork.

If you can upload pics of the fork and the cartridge I can confirm that's what it is.

 

[Jim76]

You are correct, that hex is a press fit to the lockout shaft. In theory, you could repair it by removing the shaft and dimpling it with a pin punch to restore a press fit, similar to knurling it. Practically though, it's probably better to replace it.

Does it say "super" on it? An Ultra DL with a black cartridge should be a 2000 to maybe 2003 70mm fork. It was a good fork and is definitely servicable. Seal kit is part#HD166. However, there are special tools required to do a complete job, and they aren't cheap.

The only cartridges that would fit in that telescope would be another DL70 or an FT70 from a 1998 or 99 SL fork.

If you can upload pics of the fork and the cartridge I can confirm that's what it is.

The fork itself has Ultra written on it. I will post some photo's tomorrow as its 1am here now, thanks for the rely

 

[Jim76]

I removed the damper today using a DIY castle tool I fashioned up from a 22mm socket, as you can see in the pics below the nut has separated from the stem. Im not sure if its worth trying to get this pressed backon, may as well buy a new unit.
Anyhow see the pics below, below are the forks themselves

Below is the removed cylinder with top nut not attached

Another close up, the stem the nut attaches to does not appear damaged

And a DIY castle tool from a 22mm socket with the help of a grinder.

So in a nutshell, I need to either get this cylinder fixed or source a new replacement. If it is a DL70 then I cannot get my hands on one in the UK,or a FT70 for that matter, anyone in the US or beyond have any for sale ?

Its a shame cause its a decent bike otherwise, and really need it fixed.

 

[MikeA]

Ok, that's definitely a DL70. If you are willing to ship it to the US, Mendon Cyclesmith in New York (http://www.mendoncyclesmith.com/) may have used parts to repair it. He ships internationally and you wont be the first to send him work from outside the US. I'd contact him and see what he says, it may end up being cheaper than finding another fork or cartridge in good working condition.

 

[Jim76]

Ok, that's definitely a DL70. If you are willing to ship it to the US, Mendon Cyclesmith in New York (http://www.mendoncyclesmith.com/) may have used parts to repair it. He ships internationally and you wont be the first to send him work from outside the US. I'd contact him and see what he says, it may end up being cheaper than finding another fork or cartridge in good working condition. Also, you shouldn't be able to thread that upper shaft off the piston like that, there may be other damage internally.

Okay thanks MikeA i will get in touch. I suppose the DL70 cylinder is discontinued in the US too ?

 

[MikeA]

yes, nothing that's currently available fits that fork.

 

[Jim76]

Okay, if you come across one please do let me know !

 

[Jim76]

No joy here in UK sourcing replacement DL70 cylinder, or finding anyone to repair it; so I sent it to Mendon's as advised. I do have another question if I could. With my forks in the photos above, is the air cylinder part of the fork itself (i.e its not removable) ? Thanks

 

[MikeA]

The air cylinder is removable, push upwards on the schrader valve end cap with something wood or plastic. Your air piston is probably stuck inside it too. To avoid damage using pliers, I like to remove the schrader valve core and push it out with a thin wood dowel through the valve hole.

 

[Jim76]

The air cylinder is removable, push upwards on the schrader valve end cap with something wood or plastic. Your air piston is probably stuck inside it too. To avoid damage using pliers, I like to remove the schrader valve core and push it out with a thin wood dowel through the valve hole.

View attachment 5475

Okay got it, yep the piston is likely still in there. Its hard to make out when I dont know what to look for. Theres something in there with a kind of sticky-up thing (iooks like the rubber on the end of a pencil, but made of metal); would that be the top of the piston ? Its not the underside of the valve cause its about a inch higher up the tube !
Cheers

 

[MikeA]

Should be white plastic, but that must be the piston since everything else came out with your damper like it's supposed to. It sounds like you sent the damper to Mendon and not the whole fork? If so, you are definitely going to want to replace the air piston seals before you assemble it. They are the weak link of that fork, they are o-rings (later models have quad rings) and they seem to take a compression set and leak air long before the damper needs service.

 

[Jim76]

To update, the air piston is removed, it was not stuck atall I just attached pump to the valve and it shot out easily enough, see the pic below.

Are these the only two seals that need replacing ? Does anyone know the sizes? I gues its just a straight forward remove the old and replace with new, no special tools required ?!

Im not so sure how to remove the air cylinder itself, if it pushes up and out through the fork then I expect I need to remove the lock ring on the underside of the fork where the valve is. See pic below there is what looks like a ring in there its cut so not fully circular.

Also when looking down into the tube, air cylinder removal is restricted by the tube above it where the inner rollers are attached

So do i need to remove this upper part before I can get the air cylinder out ?

Do I even need to remove the air cylinder, it looks fairly clean. If I just change the seals on the piston will this suffice or are there other seals that need replacing ? Thanks all

 

[MikeA]

The seals are a standard buna-n A70 oring, size -115. That's an AS568A standard, not sure if that's an international standard, but it's what you would get at any hardware or plumbing supply in the US. Grease them heavily with a synthetic grease on assembly, and lightly oil the cylinder. The factory uses a tacky oil like Phil Wood Tenacious.

Don't remove anything else! just push the cylinder out from underneath. That's it. You don't really need to remove it, you can put the piston on the damper and thread it into the fork with the air cylinder still in place.

 

[Jim76]

Great stuff I will try and find a metric size for those orings. Would like to take the air cylinder out anyhow just so I know how its done. Do i need to remove the rubber boot and detach that part of the fork (that the rails are in) or can I remove the air cylinder with all that in situ ?? Thanks pal

 

[MikeA]

Again, do not remove anything else!!! If you disturb the orientation of the bearings and races you're going to have a bad time. The cylinder is slid into the steerer tube from the top, normally you can just push it out from below with a wood dowel. I see you have some corrosion on the end cap so you may need a light tap on the dowel initially to break it free.

 

[Jim76]

Again, do not remove anything else!!! If you disturb the orientation of the bearings and races you're going to have a bad time. The cylinder is slid into the steerer tube from the top, normally you can just push it out from below with a wood dowel. I see you have some corrosion on the end cap so you may need a light tap on the dowel initially to break it free.

Right O thats great thanks

 

[Jim76]

I removed the air cylinder no problems there; however there was also a round spacer that came out with it, it was located ontop of the air cylinder.

Is above the air cylinder and below the air piston the correct position for this ? Ive had a look at a few online drawings for this shock and cannot seem to find it, any ideas ?? Thanks again

 

[MikeA]

It's this collar:

It will be held in place on assembly by an o ring on the damper end cap.

 

[Jim76]

Ah ok, I did not send this collar to the repair shop with the damper; is it easy to install once I get the damper back ? Or do you think I should ask them to fit one ! It looks like it will just slide over the damper spring right ?