I've found this thread and this thread and this thread discussing some of the details for refilling nitrogen shocks.

It looks like I need a nitrogen shock filler, hose, regulator, and tank.

nitrogen shock filler (shock rebuilding shop) $100
hose (welding shop)
tank regulator with input and output gauges (welding shop) $100
regulator cage (welding shop)
small tank (welding shop) $100

Does anybody have additional input for which parts to get or sourcing the parts?

Is there a standard way to check or fill nitrogen pressures?

 

The Moton shock gauge has a 1mm bore so it bleeds off only a tiny amount of pressure. It connects to the shock and then you can connect a nitrogen tank to the other end of the gauge putting it in line to the shock. You can watch the gauge as you do your thing.

 

Call Lex at Moton to see about buying a kit. I think they are around 400 bucks or so.

 

Also, RV stations often have nitrogen tanks to fill truck tires (so they don't deflate when sitting around). I found a place that will fill mine for free. My local race shop does it for me, too.

 

These will require some additional pieces (plumbing and nitrogen supply), but are a good start to a do-it-at-home kit:

RE Suspension Regulator

RE Suspension Inflation Tool

Penske Inflation Tool

Longacre Inflation tool

Gensis Tech Inflation Tool

 

FOX Shox Fill Gauge

Kartek Shock Pressure Gauge

I called Moton for a description or photo of their tool and they are out for Mid-Ohio until next week.

Since most of these are schrader-based, the other element is a nitrogen tank with a tire chuck on it. Directions are pretty straight forward:
Uncompress shock
Spin schrader collar onto shock schrader
Spin t-handle into shock schrader
Check pressure
Use nitrogen tire chuck on tool schrader until ~20psi above target
Bleed shock schrader until desired pressure
Unspin t-handle from shock schrader
Unspin schrader collar from shock

 

The Moton shock gauge looks very similar to the Kartek.

 

I purchased a regulator kit and shock pressure gauge from Kartek and 20CF nitrogen tank from Airgas. It came with everything, but knowing what I know now, I could have bought the entire rig for half the price.



Kartek's China-sourced quick-disconnect leaks under the pressures required and the tire chuck prematurely engages the schrader valve. With the low volume of the canisters, each time the chuck engages, the volume dumps and then recharges. The end result is a very imprecise process that requires wasting (and huffing) a lot of nitrogen.

My solution to this entire process is to source another threaded schrader valve to attach directly to the nitrogen source, bypassing the schrader inflation tool. The nitrogen regulator has enough control to get me the 200psi +/- 10psi that I need to start pressures at.

 

If you don't want to buy your own stuff, you shouldn't have much trouble finding someone to do it for you for free.

 

You'd think, wouldn't you?

Everybody I asked said they just pay somebody to do it but have been meaning to buy their own stuff.