Planet Minis

joman2055 · 07-10-2007, 04:38 PM

hey guys. my buddy just gave me a rear shock off his sikk 50. there is an air valve on the end of it. am i supposed to fill this thing with air or is that just for bleeding it?

thanks

-joe

RLucky82 · 07-10-2007, 04:57 PM

it should already be charged with nitrogen. 300lbs i think?

joman2055 · 07-10-2007, 05:27 PM

this one looks a bit too cheap for nitro. i could be wrong. i pressed the valve in and it went in really easy and only a small amount of air came out. so i think its empty of what ever was inside.

Z50King · 07-10-2007, 05:50 PM

most importers cannot get compressed nitrogen through customs into america, so most knockoff bikes come without charged shocks. air will leak right out, use nitrogen if you can have someone safely and accurately charge it for you

joman2055 · 07-10-2007, 07:30 PM

well, tht kinda blows. i wonder who can fill this thing. ill have to ask around i guess.

side note: my lifan 140 is in and starts!!! but the clutch cable is too short so no riding yet.

RLucky82 · 07-10-2007, 08:19 PM

Quote:

Originally Posted by joman2055

well, tht kinda blows. i wonder who can fill this thing. ill have to ask around i guess.

side note: my lifan 140 is in and starts!!! but the clutch cable is too short so no riding yet.

any respectable motorcycle shop can, even some good auto shops. if worse comes to worse use compressed air. nitrogen is just more stable then plain air. some racers use nitrogen in their tires.

joman2055 · 07-10-2007, 09:12 PM

alright. thanks.

now i need to figure out this lifan clutch cable mess.

Z50King · 07-10-2007, 10:18 PM

nitrogen in tires is used in car tires because the molecules are soo big that they leak out slower than air in car tires.

i have tried filling mine with air, and it leaks out within a day. you need nitrogen to stay in there

costco has compressed nitrogen at their tire center, but i doubt they will fill your shock for you.....

Z50King · 07-10-2007, 10:37 PM

you should press it with the valve on the top side of the shock.... oil sits on the bottom, the air will rise up and be able to check the pressure that way

VillainMotorsports · 07-10-2007, 11:16 PM

Quote:

Originally Posted by smoothoperatorsfreestyle

mine was filled with oil
i pressed it and it shot me

Your nitrogen bladder has a hole in it, the nitrogen and oil are in seperate chambers. If there's any air or nitrogen in the body of the shock (where the piston is that controls your damping) pull it apart and rebuild it, cause it's not doing you any good with air bubbles in there.

VillainMotorsports · 07-11-2007, 06:04 AM

So there's nitrogen and oil just sloshing around inside the shock? If that's the case the oil is going to turn into foam when you're riding as oil and nitrogen are passing through the piston valves to damp the rebound and compression of the spring and there will be no damping or very inconsistant damping. Maybe I'm missing something here with these shocks, but that seems kinda strange.

Z50King · 07-11-2007, 08:22 AM

i guess you could actually call that dampening if the nitro and oil are mixed together.....

RLucky82 · 07-11-2007, 09:11 AM

Quote:

Originally Posted by themountain

..are you blind?? I wrote there is a piston inside the shock to separate the gas and the fluid!!

You wrote "put valve upright to fill otherwise the oil gets pressed out" meaning oil comes out where air goes in! if thats the case then oil and air are getting mixed together like he said.

Edit: I see your from Portugal, something probably got lost in the translation...

RLucky82 · 07-11-2007, 09:33 AM

Quote:

Originally Posted by Z50King

nitrogen in tires is used in car tires because the molecules are soo big that they leak out slower than air in car tires.

I never heard that before.
nitrogen is more stable so it doesn't expand and contract as much from heat = your tires don't change pressure during a race. which is even more important on your shock.

found this some where.

Quote:

Nitrogen vs. "Air" Size

name Doug
status other
grade other
location NY

Question - Based on the paper found at

Loschmidt on Molecular Size

, given the size of an air molecule as described in this
paper, what would be the comparative size of a nitrogen
molecule? I am trying to simply quantify the theoretical
difference for a comparison between the leak rate of air from a
tire inflated with air to 30 psig and the same tire inflated with
nitrogen to 30psig.
------------------------------------------------------------------
Remember that air is already 80 volume percent nitrogen, so the leak
rate between air and pure nitrogen is not very different. In
addition at pressures of the order of 30 psig all gasses obey the
ideal gas law P*V = n*R*T so there is little gas-to-gas differences
except for Helium which can diffuse into the rubber. FYI I am told
that race cars use nitrogen instead of air to prevent oxidation of
the rubber in the tires at the high operating temperatures in a race
car tire. Makes chemical sense but I do not know that it is the case
first hand.

Vince Calder

I can't imagine that oxidation would be a problem either when your changing tires after every race. sometimes several times during the race!

SDF · 07-12-2007, 05:07 PM

It's more to do with heat, Nitrogen is less effected when heated than air,
whether in a shock or a tyre it's properties stay far more consistent when operating temperatures change.

A tyre will keep a more consistent pressure and shape giving better more controlled handling characteristics.

A shock will have a more consistent dampening and rebound control, again giving more consistency and better handling.

Part of the reason why top end shocks have piggy back or separate ressy's....

PS. Hi All .....

RLucky82 · 07-12-2007, 06:09 PM

Welcome to planetminis

ya, that kinda makes you wonder why they mount the remote reservoir right above the exhaust pipe on so many models?

Z50King · 07-13-2007, 01:20 AM

Quote:

Originally Posted by SDF

A shock will have a more consistent dampening and rebound control, again giving more consistency and better handling.

you sounded pretty intelligent until you said that

im just kidding, im sure you are very intelligent, but tell me what are you dampening in your shock? maybe you speak of the oil making things wet??

PitBoy · 07-13-2007, 04:53 AM

I've got a thumpstar bike and mine also has the little air valve. Are all these shocks supposed to be filled to 300lbs? or is this based on rider weight?

SDF · 07-13-2007, 06:52 AM

Quote:

Originally Posted by Z50King

you sounded pretty intelligent until you said that

im just kidding, im sure you are very intelligent, but tell me what are you dampening in your shock? maybe you speak of the oil making things wet??

Maybe my Scottish lingo has thrown you there ......
by dampening I was referring to (describing) part of the operation of compression.

(the effect of cushioning/dampening) not wet/moisture dampening

It's maybe a term you guys don't hear much.

SDF · 07-13-2007, 07:04 AM

Quote:

Originally Posted by RLucky82

Welcome to planetminis

ya, that kinda makes you wonder why they mount the remote reservoir right above the exhaust pipe on so many models?

Thanks mate....

Yea your right, you would think it not the best idea to mount it close to the exhaust, even if there is not enough heat emitted to warm/effect the ressy,
it would be good engineering practice to mount it else where on the sub frame.

Unless its the only suitable location of course....

07-10-2007, 04:38 PM	#1 (permalink)
joman2055 2nd Gear Member Join Date: Jun 2006 Location: San Jose, California Posts: 512	am i supposed to fill the shock with air? hey guys. my buddy just gave me a rear shock off his sikk 50. there is an air valve on the end of it. am i supposed to fill this thing with air or is that just for bleeding it? thanks -joe

07-10-2007, 04:57 PM	#2 (permalink)
RLucky82 3rd Gear Member Join Date: Jan 2007 Location: Medina Ohio Posts: 1,990	Re: am i supposed to fill the shock with air? it should already be charged with nitrogen. 300lbs i think?

07-10-2007, 05:27 PM	#3 (permalink)
joman2055 2nd Gear Member Join Date: Jun 2006 Location: San Jose, California Posts: 512	Re: am i supposed to fill the shock with air? this one looks a bit too cheap for nitro. i could be wrong. i pressed the valve in and it went in really easy and only a small amount of air came out. so i think its empty of what ever was inside.

07-10-2007, 05:50 PM	#4 (permalink)
Z50King 3rd Gear Member Join Date: Sep 2004 Location: Upland, Ca, CPP Posts: 9,879 My Mood:	Re: am i supposed to fill the shock with air? most importers cannot get compressed nitrogen through customs into america, so most knockoff bikes come without charged shocks. air will leak right out, use nitrogen if you can have someone safely and accurately charge it for you

07-10-2007, 07:30 PM	#5 (permalink)
joman2055 2nd Gear Member Join Date: Jun 2006 Location: San Jose, California Posts: 512	Re: am i supposed to fill the shock with air? well, tht kinda blows. i wonder who can fill this thing. ill have to ask around i guess. side note: my lifan 140 is in and starts!!! but the clutch cable is too short so no riding yet.

07-10-2007, 09:12 PM	#7 (permalink)
joman2055 2nd Gear Member Join Date: Jun 2006 Location: San Jose, California Posts: 512	Re: am i supposed to fill the shock with air? alright. thanks. now i need to figure out this lifan clutch cable mess.

07-10-2007, 10:18 PM	#8 (permalink)
Z50King 3rd Gear Member Join Date: Sep 2004 Location: Upland, Ca, CPP Posts: 9,879 My Mood:	Re: am i supposed to fill the shock with air? nitrogen in tires is used in car tires because the molecules are soo big that they leak out slower than air in car tires. i have tried filling mine with air, and it leaks out within a day. you need nitrogen to stay in there costco has compressed nitrogen at their tire center, but i doubt they will fill your shock for you.....

07-10-2007, 10:37 PM	#9 (permalink)
Z50King 3rd Gear Member Join Date: Sep 2004 Location: Upland, Ca, CPP Posts: 9,879 My Mood:	Re: am i supposed to fill the shock with air? you should press it with the valve on the top side of the shock.... oil sits on the bottom, the air will rise up and be able to check the pressure that way

07-11-2007, 06:04 AM	#11 (permalink)
VillainMotorsports 2nd Gear Member Join Date: Feb 2007 Location: Winnipeg, Manitoba, Canada Posts: 565 My Mood:	Re: am i supposed to fill the shock with air? So there's nitrogen and oil just sloshing around inside the shock? If that's the case the oil is going to turn into foam when you're riding as oil and nitrogen are passing through the piston valves to damp the rebound and compression of the spring and there will be no damping or very inconsistant damping. Maybe I'm missing something here with these shocks, but that seems kinda strange.

07-11-2007, 08:22 AM	#12 (permalink)
Z50King 3rd Gear Member Join Date: Sep 2004 Location: Upland, Ca, CPP Posts: 9,879 My Mood:	Re: am i supposed to fill the shock with air? i guess you could actually call that dampening if the nitro and oil are mixed together.....

07-12-2007, 05:07 PM	#15 (permalink)
SDF PM Newbie Join Date: May 2007 Location: Sunny Scotland Posts: 65	Re: am i supposed to fill the shock with air? It's more to do with heat, Nitrogen is less effected when heated than air, whether in a shock or a tyre it's properties stay far more consistent when operating temperatures change. A tyre will keep a more consistent pressure and shape giving better more controlled handling characteristics. A shock will have a more consistent dampening and rebound control, again giving more consistency and better handling. Part of the reason why top end shocks have piggy back or separate ressy's.... PS. Hi All .....

07-12-2007, 06:09 PM	#16 (permalink)
RLucky82 3rd Gear Member Join Date: Jan 2007 Location: Medina Ohio Posts: 1,990	Re: am i supposed to fill the shock with air? Welcome to planetminis ya, that kinda makes you wonder why they mount the remote reservoir right above the exhaust pipe on so many models?

07-13-2007, 04:53 AM	#18 (permalink)
PitBoy 1st Gear Member Join Date: Jul 2007 Posts: 208	Re: am i supposed to fill the shock with air? I've got a thumpstar bike and mine also has the little air valve. Are all these shocks supposed to be filled to 300lbs? or is this based on rider weight?

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