Wow...performing the IFP service is an incredible improvement. My shock must have been in bad shape from the time I bought it used.
The symptoms when riding was harsh on chatter and on some rare occasions it would feel as if the rear suspension locked up with a clunk for a 1/4 second...hard to notice, but definitely there. Otherwise as far as I knew the shock worked well enough on bigger stuff.
When cycling the shock I could hear a quiet sucking sound on rebound and the last inch would travel twice as fast Sometimes the shock would travel 1/4 to 1/2 inch before engaging. I had thought this was due to a dry seal or o-ring and it would go away after an air-can service. Another thing I noticed was that if I picked the rear tire of the bike up a few inches and let it drop I would get a loud SLAP sound which turns out was coming from the shock. Replacing the shock with a stick of wood bolted where the shock went proved that.
Armed with the Big Hucker Schrader valve mod I felt confident to get into the guts. A small amount of oil came out of the IFP gas port. A small sampler of Guinness came out of the oil reservoir. The floating piston was all the way at the bottom of the shock body. Well that clearly explains the behavior I saw.
I followed all the instructions including the hard to find (
) custom blend gas mixture rather than pure nitrogen with the exception of using Motorex 10wt Racing Shock Oil which was the closest high VI fluid to 47 cSt@40 I could find (52 cSt@40). The shock is tuned for Comp=200, Rebound=M, Velocity=L. I will ride with this for a while, but rebound is almost too slow wide open.
All I can really say is "Wow. I guess I had no idea how much better the shock was supposed to be". The rebound is silent and smooth. I have a much harder time bottoming out the shock. The pro-pedal works SOOO much better. The clackety clack which I thought was mostly chain slap in the front mech is mostly gone...replaced with only real chain slap.
I had been in contact with Fox who would have retuned the shock for $85, which is not bad. BUT having the ongoing ability to do this work myself in about 30 minutes or so is for a $30 investment (valve and oil) is fantastic. THANK YOU Big Hucker!