Nitrogen charging

[FenryHonda]

What is the average rate for charging gas shocks?

I had a set of Fox Airshox charged for $10.00 about 4 months ago, but this time I went to another dealer and he charged me $40.00. Isn't this robbery?

 

[marcusgunby]

Yes im afraid it is-you can get a complete N2 set up for a few times that price.

 

[ochster]

A little off topic...I know a shop that just stopped doing walk ins. Now if you wan't your shock charged, you pay for a oil change (1hr. shop labor). Reason was, a customer brought in a miss assembled shock, and upon charging, it blew.

 

[2001yz250]

Most shops have a minimum charge no matter what they do. Maybe yours was $40?

 

[TrailRiderca]

We have several bikes and do all of our own maintenece, but we also buy a lot of parts. I have had shocks charged at all three of the shops we regularly deal with this year and none of them wanted to be paid for this service. Maybe you need to buy more parts.

 

[Papakeith]

Same here, but for convenience's sake, I've been thinking about getting a nitrogen setup. Granted it will only be used a couple of times a year, but when I need it I'll have it. Anyone got an idea how much a charging station costs to set up?

 

[djebel250]

Guys, 2 months ago, I charged up the rear shock of my Kawasaki ZX6R ( sorry, itz not a dirt bike but i guess its related to the topic ) After a long ride last weekend with 2ups, the rear shock feels washy. don't work like before. how long does the nitrogen lasts anyway? :silly:

 

[Papakeith]

As far as I know, nitrogen doesn't go bad. There might not be enough of a charge, a valve may leak, or a bladder rupture, but that's about it as far as the nitrogen charge. To the best of my knowledge anyway.

 

[Rcannon]

I had an old suzuki DR 350 that leaked the charge out of it. I changed the valve stem with one approved for high pressure refrigeration...no mor eleaks. Expect to pay less than a dollar fo rone.

 

[smrmx]

check around you local fire ext. shop they fill them with nitrogen.I dunno what they will charge you but It might be worth it. I'm glad I work for one all the nitrogen I can use.

 

[Papakeith]

Who are some of the companies that sell the components that I need to set myself up?

 

[pro-design]

any welding supply store has what you need. For personal use get the smallest bottle they have , probably around $60.00 and a regulator 0 to 1000 psi. The regulator will be around a hundred and then all you need is a standard tire fill tool. Most bikes take 165psi.

 

[ohvrider]

Hmmm so the 150 psi of shop air isn't good for my shock? I checked it with a gauge and that 150 equals 120 after the schrader gets unhooked. It's still fine after a year of hard riding.

 

[dkortje]

I hate to go back to basics on you guys, but this is a neglected topic for me. How often do you check the pressure in the rear shock, what should it read (YZ125), and how often should the Nitrogen be charged? Regularly or just when it is low?
Thanks

 

[MikeT]

Originally posted by ohvrider
Hmmm so the 150 psi of shop air isn't good for my shock? I checked it with a gauge and that 150 equals 120 after the schrader gets unhooked. It's still fine after a year of hard riding.

Air is no good because of a number of reasons. It expands when heated so the same pressure won't be mainained, it has water in it. etc.

 

[marcusgunby]

Mike i think the water part is correct but all gasses expand at the same rate.Your point is valid however-dirty air isnt a good idea in a shock.

 

[MikeT]

I know the F1 guys and I think the NASCAR guys fill their tires with Nitrogen because it maintains a more constant pressure, so I thought. Are you sure about all gasses expanding at the same rate? Isn't that only an ideal gas? I thought if anything the Nitrogen expanded at a lesser rate than the air...... It's been a long time since Physics class..

 

[JTT]

This was discussed on an earlier thread and brighter minds than mine agreed that nitrogen does expand, as does air. Marcus mentioned the "dirty air" and I think this is the key. The moisture in normal compressed air is what gives rise to an artificially inflated pressure increase with heat. Do a search, it wasn't long ago this was discussed.

 

[MikeT]

Originally posted by JTT
The moisture in normal compressed air is what gives rise to an artificially inflated pressure increase with heat.

That's what I was thinking about.

 

[BadgerMan]

I have been running 160 lbs. of air (from a ATB shock pump) in my YZF this season as an experiment. No ill effects whatsoever. Subsequent tear-downs/oil changes have shown no corrosion inside the resivoir.

My hunch is that you would get more moisture from a compressor (unless you run a dryer in the line) than from a shock pump.

 

[MikeT]

I think the air will contaminate the oil much faster than the metal impurities will contaminate the shock oil. If you are frequently tearing it down, then you might not have a problem except if (as stated by JTT) the moisture causes the pressure to increase too high and blow the seals...

 

[BadgerMan]

The air never touches the oil.

I have had no such problems with pressure increasing. If I did not have to remove the exhaust from my bike to access the valve, I would take some readings before and after riding just for curiosity's sake.

 

[MikeT]

So (you can see I've never rebuilt a shock myself) if the air never touches the oil, then is the only real reason for nitrogen instead of air, the moisture? Who here really knows the answer??

 

[Papakeith]

Nitrogen is predictable. Compressed air, will have impurities (water is one) that make for an unpredictable rate of expansion. So, I imagine they use Nitrogen to eliminate having yet another variable in the suspension.

 

[MikeT]

So if you used "filtered" dired air you should be fine then. Right?