Help Jer or anyone .Where did the fork oil go?

[eunos]

Can anyone help?
I recently serviced the forks on sons 426,I did everything by the book, including measuring how far to move the leg up and down when first priming (sad or what?). I filled the fork oil to within 100 millimeters of the top knowing this measurment worked for the jumpy track we were going to.The bike was then left for 2 weeks until we were informed the venue had changed to a flat fast sandy track so I decided to remove another 30 mm of oil.When I removed the caps & springs I found 1 leg with no visible oil in it and the other with approximately 10cc visible over the top of the damper tube. Can anyone explain what happened? All the seals etc are fine with no leaks.

 

[marcusgunby]

To fill them properly you have to fill them to the top-leave for 5minutes for the air to come to the top,then remove to the level required, once you have used the forks the level will alter slightly but not much if the air was left to come out.Maybe the damper rod wasnt fully filled with fluid.

 

[eunos]

Thanks Marcus,
I`m pretty certain it must have been the damper tube not filling, we had removed this to replace a shim in the valve stack.After filling I left the forks to bleed air for 10 mins, I have noticed what maybe an oversight on Yamaha`s part, in the service book, they make no mention of pumping the forks with your hand over the top to force oil into the valves.Both Honda and Kawa recommend you do this, perhaps this is why the damper did`nt fill.