Hi anyone know who made this shock and how it works. It has a valve on the little tank I assume is for air. Just go this 1987 k75s 

I'm pretty sure it's not a Works Performance shock.  Doesn't look like any of those shocks that have come through my garage. It might possibly be a Fox.

What is that large knob on the lower end of the reservoir? Is it a knurled aluminum knob?  Is there another knurled ring on the lower end of the shock just above the mounting eye?  If so, there is a chance you have a Fox Twin Clicker which is a pretty good unit that still has some rebuild parts available for it.

https://www.ridefox.com/service.php?m=moto

http://mahonkin.com/~milktree/motorcycle/fox-rebuild/Fox-twin-clicker-rebuild.pdf

http://evolutionsuspensionproducts.com/FTC.html

I've had several of those Fox Twin Clckers and rebuilt one of them myself.  With adjustable preload, and compression and rebound damping you can get them adjusted for a pretty good ride.  Of the 4 or 5 different shocks I've had on my Bricks the Fox is my favorite.

It seems to have some construction characteristics in common with the Progressive Adaptive shock absorber (pictured below) found on another old Brick recently.

I looked at fox and it is close but the progressive shown is it. If anyone has had experience with this shock I would like to know. It ain't shiny now but if it is decent and works is will be shiny again.

lucki wrote:I looked at fox and it is close but the progressive shown is it. If anyone has had experience with this shock I would like to know.

I haven't yet found any information about this relic.

In the absence of information, I recommend that you contact Progressive's technical department directly by using this email address. In the Subject line write, Information about Old Progressive adaptive shock absorber, then describe the age of your Brick and the situation. If you can paste the photos of the component with the Progressive sticker and the shock itself from this thread into the email, so much the better.

Latch
Any chance you can see a.model or serial number on this shock?

As per your suggestion to contact progressive, just did it now. Put a tire pressure gauge on the valve, no pressure on tank. Will put in about 10psi see if it holds.

lucki wrote:Latch
Any chance you can see a.model or serial number on this shock?

It'll need some steel wool scouring to reveal any clues, but to start off, there could be something in this area.

That's an odd place to mount the reservoir. Usually people mount them on the right rear frame rail. Like this:

10 psi is not enough to know if it holds pressure.  Those reservoirs are nitrogen charged with at least 150 to as much as 300psi.  The amount of gas charge is pretty small, so it's possible it all came out when you tried to check it. 

Tire gauges are not the way to check them.  They require a special test/charge setup and a high pressure(1000psi bottle) nitrogen source.  That charge is the only part of a rebuild that you should leave to a shop.

Confused now. So can it be used as is or scrap it. I'm not going to be scraping the pegs.

lucki wrote: So can it be used as is or scrap it. I'm not going to be scraping the pegs.

It's capacity to hold oil and gas pressure to function as intended needs to be determined by an experienced technician with suitable gauges and tools. Control of a motorcycle can be lost without scraping peg; just hitting ruts or potholes at speed can cause handling control problems if the rear shock isn't working correctly.

Are there any motorcycle shops in your area?  It sounds like you live in a rural area. 

If you can find a shop that sells sleds, ATV's and bikes, their shop will probably be able to do some rebuilding.  They can at least remove and install the spring and charge the reservoir.  Those are the only jobs you might not be able to do yourself.

You have nothing to lose with your present shock.  It sounds like you have removed the gas charge, so if you can remove the spring you can play a bit with the rest of the shock. 

The reservoir should have either a floating piston or a bladder that keeps the nitrogen from mixing with the oil.  One end of the reservoir will have a cap that is either threaded on or held in place by a ring in a groove. 

The shaft and piston in the body of the shock are held in place by a threaded cap on the end of the shock body.  There are several different ways these caps are turned to loosen them.  A good close up photo with the spring removed will help identify what tool you need. 

Internal parts usually include a shaft seal and a handful of o-rings to seal the pistons in the body and the reservoir.  If you find a bladder in the reservoir and it has a hole in it, unless Progressive can replace it, that will be the end of the line.  Otherwise, an evening of puttering and a few bucks in parts will get you back on the road.

Took it out for first run yesterday, about 20km on rough roads. I must do something about that rear shock. Try to have it filled .
Anyone have a suggestion about low cost replacement.

Looked on ebay, some vendors in Italy , anyone delt with them?

Can you see any oil leaking at the shaft?  If not you may be able to get away with a recharge.

Have you been able to get a response from Progressive?  I would think they could provide you with information on charging and/rebuilding your shock.  I suspect that you may have lost the gas charge when tried to check it.  Without a specification for the pressure I would give it a try at 150psi. 

Are there any shops nearby that sell and service ATV's?  A lot of the ATV's now have gas shocks and the service departments should be set up to charge them.  If you take the shock to them they can usually charge it in 10 minutes for about $20.  It's not rocket surgery, basically, it's like putting some air in a tire, just at a much higher pressure. 

The pressure is needed to prevent cavitation of the oil as the piston travels up and down, and to put some pressure on the lips of the shaft seal to help prevent leaks.

Got a reply from progressive, said it was a 420 no rebuild kit. So if does not hold pressure it is junk. No visible oil leaks.

I suspect will be looking for aftermarket shock. Ideas?

Yikes, shop wanted $100 to charge shock! Might as well put the 100 towards a new one, but which one.
Looked On ebay, saw lots of Chinese and Italian shocks bewildered.
For all I ride not willing to pay a fortune.

I have an OEM shock that works around here somewhere.  I can't remember what I paid for it, but you can have it for $25 plus shipping.

I may take you up on that generous offer. However, today my neighbour who is lead mechanic for a snowmobile dealership came over. He is taking the shock in to work monday. Said likely. Gas leaking by the piston in the canister. Also he has seals that might fit. Felt if all goes well might get a couple more years out of it. For 50 bucks seems worth a shot. I'll let you know how it goes.

That's good news! 

You know, somebody put that shock together, so somebody else should be able to take it apart and replace the worn parts.  Let's hope your neighbor can do it.