Front Shocks

[hydraulicman]

I run "0" PSI in my front shocks and have found that air pressure is building up in the shocks. The right shock seems to build up faster than the left and I do not understand why.

I removed the air valve this morning and noticed oil on the valve. This is making me wonder if the oil seal is leaking and that is what is causing the air pressure to increase.

Has anyone seen this before? Would this be a warrenty problem? I have an 06 RSV that was purchased in 07 so I still have some warrenty left.

Thanks for the help.

[Bummer]

You should still have some warranty left. Seems like a good time to use it.

 

Please let us know what you find out. I'm interested in how you can have pressure buildup in a system that you have to use a hand pump to add air to.

[dingy]

The seals are located at a point in the shock system that should always have oil above it, this is of course inside the inner fork tube.

 

That being said, you would almost certainly have a noticeable oil leak, prior to anything serious enough to suck air into the system.

 

Are you noticing the air build up after riding? It could be that due to heat buildup inside the forks, the oil is expanding slightly, giving a higher pressure reading when warm.

 

Is the oil level identical between the two forks? A difference in oil height could explain the difference in pressure between the two forks. The fuller tube would have a higher pressure reading when heated up. More oil to expand and less of an air space to absorb the increase would result in higher pressure.

 

Gary

[Rick Butler]

Barry,

 

I really wouldn't worry about this condition. Remember, the fork itself is a sealed confined space with oil in the bottom and trapped air above it. And it's also a piston that compresses when fork goes down and creates pressure. So if you let all the air out when the bike was just sitting on the sidestand, when you sat on the bike and measured the pressure, you would find that it would read something higer than 0. And to get the exact pressure reading from both forks, the bike really needs to be sitting straight up.

 

And oil on the schrader valve is not really an indicator of a seal not holding. I'm not sure exactly what goes on inside a fork as the bike goes down the road as it compresses and rebounds from the road surface, but I'll bet that oil is going everywhere inside of this confined space. If one of the two seals were leaking, you would have oil running down the fork lower. And if you still have the oem springs, you only have about 3" or less of usable fork travel left of the total 5.5". This is why the best thing you can do to your front suspension is replace the springs with a set of heavier Progressives or 1.2kg/mm constant rate springs along with fresh fork oil.

 

Hope this helps,

 

Rick