[greenblinker104]

The lowers on my 2003? fox van just broke last week so i bought a 2005-2006? fox float r to replace it and lowered the travel from 130mm to 80mm tonight.

Now the fork has a bad feeling/sounding top out. It happens in any pressure. I lowered my fox van and the float is much simpler to lower and i followed the fox manual so i know i didnt miss any steps. There might have been a cc or two less of oil in the bottom of the leg (requires 30cc) or a cc or so less of float fluid (requires 5cc) but i dont think that either of those would cause a top out in the travel.

Any ideas or anyone whos had this experience after lowering their fork? If i cant figure this out, ill just get some new lowers on the van and rebuild that fork...

*EDIT*

so after not actually being lazy i did some psi tests. one thing that i found interesting is that between 50psi (rider weight = 125ish) and 80psi (rider weight = 180ish) the fork stanchion showing increases about 15mm which i dont like. sure im adding more psi to the system but i wouldnt think that the travel would technically "increase" from that.

also, i found that the top out goes away in the 50-60 psi range but when i dial it up over 80psi it begins again. the topping out im pretty sure thus is caused by the pressure being too high and there not being enough range in the rebound damping to combat the increase in pressure and harshness at the top of the stroke. so the topping out is more of a super fast rebound. so im guessing that i can solve my top out issue by slowing down the rebound in the fork - not sure if i can change the rebound range to be more functional with the higher psi range that i will be runnning (this is going on a street bike so looking for max-ish psi which for fox is 125)

so, anyone ever deal with this??

 

[Dirtjumper999]

Typically harsh top out in any fork is caused by either not enough oil in the rebound damper, or one of the seals in the damper is shot/broken/completely gone. You will hear the top out more with more pressure in the air spring of course, but its not the cause of it. I suggest taking the entire damper out and cleaning the hell out of it, check all of the seals and replace those that need replaced. Coat all of the seals and moving parts with slick honey, and then put it back together with new oil. If that doesn't fix the issue, then you may have something a bit more serious on your hands. When you take out the uppers, you will see this hard plastic seal at the bottom of the stanchion, SOMETIMES this can get damaged to the point of where it can be moved a good 5mm up and down. I have only seen this twice, but this allows the oil to squeeze through that seal and the stanchion, needless to say if it moves this much, you'll need to replace that. But at that point, send it to Push and get them to do a full overhaul on the entire fork.

 

[Dirtbike]

Sorry for the late reply, and you may have figured it out by now, but here is why your fork is topping out.

Fox float forks use a coil negative spring on the shaft under the travel spacers. The stock spring rate is designed for use with low pressures and XC use. When you increase the air pressure, the negative spring, which is too soft, compresses completely and can no longer cushion the topping out and causes a clunking sound, and poor feel. The spring can be replaced with a stiffer one, as I have done this to mine. I got the part from fox but it is my understanding that they do not sell the part. This was a couple years ago and things may have changed. Give them a call and they might be able to help you out.

Chris