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Discussion Starter · #1 ·
I just changed the oil in the lowers and after putting everything back together I'm bottoming out way too easily even at max PSI. I'm a big rider, around 250 with gear, so I was running about 110 PSI before. That seemed to work pretty well. I was using most of my travel, but not bottoming out. Now even at the max pressure of 120 for this fork I can bottom it out just bouncing on the bars in the driveway.

I guess I can add more volume spacers (there are two in it now), but this seems a little extreme. Is it plausible that greasing the seals and putting in freshly soaked oil rings made this much difference or did I screw something up? I did not touch the air chamber so the volume of oil in there shouldn't have changed.

I've serviced forks before and had to put in more PSI as a result, but like I said this seems excessive. Even when I serviced my old Raidon that hadn't been maintained in 3 years it didn't make this much difference.
 

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I'd cycle the fork a bunch & recheck air pressure. Perhaps some of that 120 psi was transferred to the negative chamber lowering your positive air pressure.

I know there is an air transfer dimple to auto adjust negative air pressure.
 

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Discussion Starter · #3 ·
Well, figured it out. It was sort of negative spring related. And it was indeed a screwup on my part.

I actually tried equalizing the negative spring last night. I could hear the air transferring, and it did seem to equalize as I dropped the pressure. But wait! It wasn't quite using full travel. I could pull up on the bars and extend the fork a little when it should have been topped out. I didn't think hard enough about that at the time, but as I was writing a response it occurred to me what happened.

I put the lowers back on with the air spring not fully extended (I let all the air out before taking them off, which I guess I didn't need to do). When I pumped it back up the lowers extended, which created a slight vaccuum in them. Basically a second negative spring pulling the uppers down.

I just used the zip tie trick to burp the lowers and sure enough, some air transferred on both sides. As soon as I did the second stanchion the fork extended to its full travel and it feels like it did before. :thumbsup:

So I guess this is a cautionary tale for anyone looking to do their first service on a fork with a negative spring. Make sure the fork is fully extended before bolting the lowers back on.
 
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