Hi, I have a 2006 Marzocchi Drop-Off 3, 150mm travel with the 20mm TA.

I serviced the fork this january and even with thicker oil than stock I can't get the rebound adjust to work decently. About 75% of the adjust don't do sh!t and a difference can only be felt when you get to about 80% of the rebound valve closed. Even at minimal rebound setting, the fork is nowhere near what it should be. I have to ride with rebound almost fully closed pretty much all the time. Stock oil was Marz 7.5wt. I used Bel-Ray 5w at first since I had some on hand but the whole damping action was too fast. Then switched to Bel-Ray 10w in the pumping element (left leg) and a mix of 5 and 10 in the rebound and preload assembly (right leg) that get me to around 9w. The whole fork is slower (in term of feel, like if it was heavier), but the rebound valve did not any better, even with thicker oil than stock.

Everything else works fine. One thing however is when I drained the old oil, there was not a lot in the right leg (rebound) compared to the left leg, even thought every manuals I read for this fork specs the same oil volume in both legs. If I remember correctly, the old oil level was not even over the rebound valve when fully extended, and when I re-filled the new oil, I noticed that if the oil wasn't at least just at the top of the rebound valve, the fork would spring back quickly in the first part of the travel till and will act more "normal" further when the oil go over the valve. Could this be the reason why I have such a fast rebound action now ?

Should I drain oil a bit to prevent oil from going over the valve during compression (so it's only air that will do ?

Thanks very much for the inputs