83 XL600R how much fork air pressure


23 replies to this topic
  • Kenzo

Posted March 13, 2008 - 05:08 AM

#21

I like the idea of maybe trying the nitrogen in the forks. I have a "generator" at work. Maybe I'll put 1-3 PSI of the stuff in my forks for the April ride and see how it works. It wont reallly increase in pressure with heat like comp. air will.... Maybe it could work?


maybe nitrogen for ur tires but not really needed for the forks...

when a gas is compressed it heats up and when it expands(un-compresses hahahaaa...is that a word?)it cools so the net temperature effect in the forks is zero except for friction...the only exception is hydrogen gas which is the opposite(cools when compressed & heats when it expands).

the rear shocks being a sealed system uses nitrogen to increase the longevity of the oil...no oxidation or moisture with dry nitrogen gas.

the forks have a very small volume to hold the pressure so setting the pressure is difficult...just by checking the pressure u drop the pressure 1-2 psi...that's why i overfill and bleed it down to the desired pressure.

in the XRL forks ~5 psi makes a significant difference with everything else left stock and compression set near the factory reccomended setting...reduces fork dive with the trade-off being a little added harshness as i posted previously.

:thumbsup:

  • Denn10

Posted March 13, 2008 - 06:49 AM

#22

i'm not really stating my opinion but rather science as far as it being only 10 psi higher...

http://en.wikipedia....i/Ideal_gas_law

i'll repete myself...adding a little air pressure may not be the best solution...half the people who try it like it the other half hate it BUT adding air pressure within spec will NOT blow the seals, will NOT cause them to leak and will NOT put ur eye out. :eek:

the specs for the pressures are in the manual(s)...argue that the manual is incorrect if u must but keep in mind that these forks are 1990's technology(if not even earlier) EVEN on the 2007 model year.

also keep in mind if/when u increase ur fork oil fill level ur only decreasing the volume of air over the same stroke length (i.e. volume)...this is VERY simular to adding preload air pressure(but not exactly the same)...it's all based on pyhsics.

:thumbsup:


i do know its science but stating that there is in fact no problems with adding air pressure to your shocks and how it isnt a bad thing is kinda an opinion!:D if it was the best way to adjust compression in forks it would still be widely used today, and saying that some bikes still has them isnt really a good argument cuz its old technology that they just keep using cuz there cheap and not updating some bikes that have them. Adding a few ounces of oil vs adding 10 psi of air is not even comparable, well on a smaller scale it is. Raising the oil level by 1/4 or 1/2 inch then compressing the remaining air in the forks wont raise the internal psi near as much as adding 10 psi to the rest of the fork chamber before you compress them. thats why its my opinion that adding pressure to forks is harder on them since your changing the internal pressures. and yes ive had a few bikes with old school forks and used air in them but never more than a few psi, maybe 3 at most.

dry nitrogen would be better i think cuz depending on your area and climate, ie dry desert vs 99% humidity seattle, ill bet you would see some contamination to your oil from the mositure in the air.

ive had some bad experiences with loading the heavy ass pig in my nice lifted beast but im about to load that bad boy up in the back and do some testing now.

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  • martinfan30

Posted March 13, 2008 - 08:30 AM

#23

Keep updating. My pig could use a little fork help!

  • Kenzo

Posted March 13, 2008 - 02:05 PM

#24

i do know its science but stating that there is in fact no problems with adding air pressure to your shocks and how it isnt a bad thing is kinda an opinion!:ride: if it was the best way to adjust compression in forks it would still be widely used today, and saying that some bikes still has them isnt really a good argument cuz its old technology that they just keep using cuz there cheap and not updating some bikes that have them. Adding a few ounces of oil vs adding 10 psi of air is not even comparable, well on a smaller scale it is. Raising the oil level by 1/4 or 1/2 inch then compressing the remaining air in the forks wont raise the internal psi near as much as adding 10 psi to the rest of the fork chamber before you compress them. thats why its my opinion that adding pressure to forks is harder on them since your changing the internal pressures. and yes ive had a few bikes with old school forks and used air in them but never more than a few psi, maybe 3 at most.

dry nitrogen would be better i think cuz depending on your area and climate, ie dry desert vs 99% humidity seattle, ill bet you would see some contamination to your oil from the mositure in the air.

ive had some bad experiences with loading the heavy ass pig in my nice lifted beast but im about to load that bad boy up in the back and do some testing now.


i'm about spent on this subject and repeting myself but...

page 67 of the Clymer Manual

(quote)FRONT FORK

Air Pressure Adjustment

Adjust the fork air pressure (Table 10) to match rider and load weights as follows: (end quote)

:D

i already posted the specs...

adding nitrogen really isn't going to hurt anything but u can't draw a vacuum on the forks to get a meaningful air-free nitrogen fill.

i stated several times it may not be the best way to adjust the forks but it is designed to do so...capish?

...heavy ass pig? try loading a KLR...

...go ahead u can have the last word :thumbsup:

:eek:





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