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09 gas gas pro fork oil


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hi all,how much fork oil goes in each leg on a gas gas pro 2009

Marzocchi's really need to be set by oil level, not volume, unless they are totally dry.

160mm for the aluminum tube and 180mm for the steel tube types.

Jon

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Marzocchi's really need to be set by oil level, not volume, unless they are totally dry.

160mm for the aluminum tube and 180mm for the steel tube types.

Jon

I believe thats with the forks fully extended with springs in, measured from the top of the leg to the top of the oil.

Also one leg takes more than the other.

Al

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I believe thats with the forks fully extended with springs in, measured from the top of the leg to the top of the oil.

Also one leg takes more than the other.

Al

Al,

Actually fork "oil level" is measured in a different way than what it sounds like and it's easily mistaken as to how the proceedure is undertaken.

Due to the different internal construction of the Marzocchi forks, as opposed to the earlier GasGas forks that are usually easily set by volume, the "Zokes" are more difficult to drain the cartridges completely. When they first came out riders were having a problem with overfilling them after servicing even though it seemed like all the fluid was removed from the assembly.

If you want to be accurate when servicing/adjusting forks you will always use oil level rather than fluid volume (all good suspension shops will always use oil level instead of volume when there is a choice). Adjusting that "air gap" (the 180mm for steel tube and 160mm for aluminum tube on the Marzocchi's for instance) measurement is also one of the ways you can change the way your forks perform.

The air gap, of course, can be adjusted to plus or minus the standard measurement to a degree and the gap affects the last third of fork travel. Say, for instance, you are having a problem with the fork bottoming out on big drop-offs and you don't want to change the oil viscosity to a "thicker" oil because that would affect the damping across the board, especially in the first/mid stroke of the fork, which you are happy with (and the thicker fluid would make the fork less reponsive to smaller obstacles). You could decrease the oil level measurement from say 180mm to 170mm, which would leave a smaller "air gap" at the top of the tube when the fork is fully compressed. That "air gap" acts as a secondary spring and like coil springs, when you shorten them, you make them stiffer (increase the "spring rate".)

This way you can target the fork problem area (bottoming out) you want to perform differently without affecting the other areas (overall damping) you want to stay the same.

The standard proceedure for measuring oil level is: spring removed, cartridge completely free of air and the top tube fully collapsed into the lower leg. The measurement is taken from the rim of the top tube down inside the tube to the level of the oil with the fork tube straight upright.

Jon

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