Hi, i bought my '06 scorpa (first trials bike) last year already with this problem, but i thought it was normal because trials bikes have more losen hydraulics. Right now only the spring is doing something, the hydraulic is not working at all. It's not leaking oil and i don't know even if it has oil in it maybe that's the problem, idk. Someone already has had this problem? What have you done to solve? 

Did you try adjusting the shock dampening adjuster?

Yes, it makes a slight diference i guess, but it´s so slight you can barely notice, like really almost no difference.