arrrrrr i cant find a way....... someone must know...

mkf

how on earth do i get air in the negative chamber of my dual air forks without it all coming out when i unscrew the pump.

is there a susp pump out there with a non-return valve i can but

angry_bird

It shouldn't all come out. Using a shock pump? You'll hear some air come out when you unscew the pump but that's the air leaving the pump itself, it shouldn't be leaving the chamber at all.

nicklouse

just remove the pump. it does not come out of the fork unless the valve is faulty.

make sure the fork is not vertical or you will lose some lube.

cooldad

The air chamber is small. Air you hear when you unscrew the pump is in the hose.
If you put the pump back on to check the pressure the air needed to charge the pump will reduce the pressure significantly.
Just pump it and leave it.

386ka

What kind of pump do you use? And what model?

mkf

using the shock pump you get with your forks.
air diffinitely coming out when i unscrew the valve cause oil comes out with it,
tried unscrewing as fast as i can, helps a little but cant do it fast enough.

:idea: might try getting girlfriend to pump and i screw the valve in just to the point of open so that when i unscrew the chamber will close faster.
any other suggestions
ta peps

Dirtydog11

Turn your bike upside down prior to connecting/disconnecting the pump to the negative chamber or you'll end up with no oil in it.

Try another pump, as others have said some air loss is normal and is usually just waste air escaping from the pump

386ka

My pump has a small valve at the other end of the connector, that when you unscrew that valve, it releases the schrader valve needle, closing the fork chamber. After this, I can remove the pump without air escaping from the fork.

cooldad

Like this

386ka

Like this, you literally have to undo the red valve...

cooldad

Mine has a clicky thing like the one I posted -seems a bit easier.

cooldad

This one - the bit of red makes it pump quicker as well.

nicklouse

totally not needed.

dont have one at the shop and never had any need for them.

cooldad

TBH the Magura one came with a set of forks. My other is a basic no name brand that works just as well.

386ka

nicklouse wrote:

totally not needed.

dont have one at the shop and never had any need for them.

If I try to disconnect the pump without doing it, I will lose some air in the process.

cooldad

You won't, that air is in the tube.

386ka

cooldad wrote:

You won't, that air is in the tube.

It is not air in the tube. It leaks while diconnecting the valve, because it does not make good seal, and the schrader valve needle is still depressed. That's why the red knob is there to undo first.

johnsav

sorry but your wrong ^

my pump doesnt have this mystical red knob and it works fine. Oh, and it says ROCKSHOX on it. I'd like to think they know what pumps are best?

386ka

johnsav wrote:

sorry but your wrong ^

my pump doesnt have this mystical red knob and it works fine. Oh, and it says ROCKSHOX on it. I'd like to think they know what pumps are best?

By having no "mystical red knob" on your pump doesn't mean that I am wrong. It means that your pump was designed not to need one. My pump is not RS, it is an aftermarket one, from XLC. And because it wasn't supplied by the manifacturer of my bike, doesn't mean that it sucks.

bails87

As I've written before:

Think about it.......

You pump up the forks to, say, 100psi. The air in the pump, in the hose and in the fork is all one 'chamber' of air all at 100psi.

You begin to unscrew the hose from the fork, the valve seals, so the forks are still at 100psi. The pump and hose are still 100psi.

You completely unscrew the valve, any air pressure above the atmospheric pressure (15psi) escapes from the pump and hose, but stays in the forks.

You start to screw the hose back onto the fork. The pump and hose are now sealed, with the 15psi of air trapped inside them.

You screw the hose on further, the valve is opened, air rushes from the forks to the pump and hose, to equalise the pressue rather than having 15psi in one part of the 'chamber' and 100psi in the other part. You end up with something in between the two, say 90psi.

Then you look and go "oh maaaan, my shock pump's lost 10psi"

If your shock pump releases air from the forks while it's still attached then it's knackered, buy a new one.

nicklouse

or the fork valve is.

386ka

I don't know why nobody understands me. Maybe because you've not used a pump like this. When disconnecting, the pump valve needle (needed to depress the shock valve), is sitting lower than with most pumps. That's why I have the red knob, which pulls the pump needle from the shock valve, effectively sealing the fork chamber.

If I try to disengage the pump without releasing the red knob, at some point in the disconnecting process, the pump valve will stop making an airtight seal over the shock valve, and with the shock needle still depressed, the shock will start losing air.

Linky to the pump: http://www.xlc-parts.com/produkte_detai ... etail.html

Features:
no pressure loss thanks to safety valve

bails87

.......so release the red knob?

If you're not using it properly then no, it might not work properly. I don't know what you expect :?

m1tch666

This is the pump I have as well, no issues, pump until correct pressure, release red valve, then release big valve. Slight sound of air releasing from the pump but not from the fork.....simples.

386ka

@bails87
I was just proving my point...

@m1tch666
Yep, easy as that.

bails87

:? What point?

That if you use your shock pump incorrectly you might have issues. Well.....yeah. But lots of shock pumps don't have the system you've described and they work fine. If you've got that system then use it, if you haven't then your pump will still work fine.

mkf

386ka, i know exactly what you mean.
i think what others dont see is that when the pump screws in its pushing the fork valve needle too far in. so with the chamber pressurized and the pump valve is unscrewed there will be a point when the seal in the pump valve breaks from the threads but the needle inside is still edngaged with the fork valve , at this point there is still maybe 3,4 turns before the pump can be pulled off, this is when air is lost from the forks.
the amount of air lost from the forks is dependant on the speed at which i can unscrew those last 3,4 turns.your little red button allows that to be done in an instant, faster seal = little air lost.

i use to have an fox shock pump that had a pull off valve,like the ones at petrol station,that work great little air lost from forks and shocks due to faster disenagement.

can't get one anymore so i'm going to buyone of yours thanks for the link

386ka

Mkf you're very welcome. I am glad I helped.
Bails87, you might want to reread the whole tread...

bails87

386ka wrote:

Bails87, you might want to reread the whole tread...

What? What point were you making?

Any shock pump, correctly used, will work with the OPs forks. If it's not working it's because there's a problem with the forks or the pump.

386ka

bails87 wrote:

386ka wrote:

Bails87, you might want to reread the whole tread...

What? What point were you making?

Any shock pump, correctly used, will work with the OPs forks. If it's not working it's because there's a problem with the forks or the pump.

Some were sugesting that my pump was knackered... Anyway, I think we got to the bottom of it.

bails87

386ka wrote:

bails87 wrote:

386ka wrote:

Bails87, you might want to reread the whole tread...

What? What point were you making?

Any shock pump, correctly used, will work with the OPs forks. If it's not working it's because there's a problem with the forks or the pump.

Some were sugesting that my pump was knackered... Anyway, I think we got to the bottom of it.

I can't see that anywhere, but yes, it's sorted now

Happy trails