I replaced the 38mm Paioli front fork oil on my 1996 Beta Techno and it was pretty dirty and thin. I noticed smoother fork action with the new 5wt oil. 

I suspect the rear shock oil is also in poor condition as well. Can I replace the oil in this shock? I think it is non adjustable, but have not seen the top of the shock yet.

I have rebuilt Showa and WP pressurized shocks on enduro bikes, but never tried a trails shock before.

Yes, can be repaired

 

Thank you so much! 

I just watched your shock repair video. You are very talented and resourceful! I am impressed. Thanks again.