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15 psi... lol...

I think I'd bump it up a hair from that :D

Go with 150-175. That's a good all-around pressure.

And I'd check the pressure again - with a nitro setup handy - in a couple weeks or so, just to make sure the valve stem isn't leaking, or the bladder isnt' damaged.

:cheers
 

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Discussion Starter · #4 ·
thanks guys.

I was pretty sure it would be around 170 from experience from my motocross days , the ohlins on there know has 195 in it. I just wanted to know what the pressure is from the factory.

I'm pretty sure my kids got to it and had a play, little fingers and curiousity is probably the cause.

I took it off the bike basically when it was brand new , so it should be fine.

thanks again.
 

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Discussion Starter · #5 ·
Thanks for the offer Gixxerracer317 , but i'm actually selling this one too, and one off my 1000.

just wanted to make sure who ever bought it , got a working shock
 

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just took a check on mine today after a little ride .. it was @ 125psi so I bumped it up to 180psi and took it out again .. feels better more planted. Might play with my setting again now or would that really change anything?
 

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Discussion Starter · #7 ·
The nitrogen under pressure is to stop cavitation in the shock and stop bubbles forming in the shock oil.

Damping will be more consistent now , shouldn't really need to adjust anything although it will probably feel firmer, but it will be quicker/more compliant in dealing with bumps.

Oil without bubbles in it will exert more force and open the shim stack quicker for high speed and move thru the piston slower for the low speed damping.

The shock/shim stack will now just work as it was designed to.
 

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I know, it's an old thread;
But- important to me.

On my '97 GSXR 750- it looks as though the stock rear shock is on there.
Manaual says 142psi of N2 gas. I'm assuming that is with the wheel off the ground on it's rear stand, etc.

Before I check it,

Has anyone ever checked theirs, and then added some ambient air pressure to what's left in the nitrogen to get it
up to say 150psi?

While I'm at it, for the front- is there any gas/air charge on the front USD forks?
Please, if you don't know, or haven't done this- please spare me your opinion if you really don't know for sure.

TIA,
Todd
 

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Todd,

Manufacturer's state that the use of nitrogen in a shock of this type, is to reduce the pressure rise, caused by frictional and compressive heating.

Pure nitrogen is more stable when heated, the pressure only changes very slightly from when the shock is cold, to hot.
You've probably seen tire shops recommending nitrogen over air, for use in passenger tires...same reason race cars and bikes use it in their tires...consistent pressures.

A nitrogen atom is physically larger than an oxygen, carbon or most other atoms in the air we breathe...so it leaks less.

Pure nitrogen isn't flammable, so that's important in certain applications. There also isn't any moisture, compressed air contains enough moisture to corrode internal parts. However, your shock gas is in a bladder.

Hopefully, that explains why you should not add compressed air to nitrogen.

If the pressure is low, you may also notice oil leaks (is there dirt sticking to the shock body?), indicating seal failure. Find a reputable shop to service your suspension.

No, there isn't pressurized gas in your front forks.

Cheers,
Scott
 

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:serious::serious::serious::serious::serious::serious::serious::serious::serious::serious:
Todd,

Manufacturer's state that the use of nitrogen in a shock of this type, is to reduce the pressure rise, caused by frictional and compressive heating.

Pure nitrogen is more stable when heated, the pressure only changes very slightly from when the shock is cold, to hot.
You've probably seen tire shops recommending nitrogen over air, for use in passenger tires...same reason race cars and bikes use it in their tires...consistent pressures.

A nitrogen atom is physically larger than an oxygen, carbon or most other atoms in the air we breathe...so it leaks less.

Pure nitrogen isn't flammable, so that's important in certain applications. There also isn't any moisture, compressed air contains enough moisture to corrode internal parts. However, your shock gas is in a bladder.

Hopefully, that explains why you should not add compressed air to nitrogen.

If the pressure is low, you may also notice oil leaks (is there dirt sticking to the shock body?), indicating seal failure. Find a reputable shop to service your suspension.

No, there isn't pressurized gas in your front forks.

Cheers,
Scott

Thanks Scott

Understood.
I'll consult my local dealer/shop to see if they can check it/charge it.

Todd
 

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I know nothing about this, but you might wanna search out local tire shops offering nitrogen tires and service. 142 psi is pretty high but if they can do it, I bet they'd hook you up cheaper than a dealer.
 

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When heated any gaz is going to expend. This is a universal rule, applying to any gaz (as long as you are far enough from it liquification....
Nitrogen is no better at this than any other gaz. The ONLY reason to replace Air by Nitrogen is getting rid of the 20° Oxygen.
Oxygen is NOT going to expand more though...however is is (as its name suggest) and Oxidizer and it will oxyde the shock oil ... even faster because of pressure and temperature.
Basically à 5 barg the oxygen contained in air could just BURN the oil, at 10 barg if you have a fine mist of oil in the shock you basically have a diesel engine situation....
Relax, it won't "explode" but it will probably oxyde your oil a little faster than pure Nitrogen (or any inert gaz).
 
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