Rockshox yari rc 160mm solo air not returning to full travel

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Rockshox yari rc 160mm solo air not returning to full travel
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Posted: May 16, 2019 at 18:00 Quote
Bnito wrote:
Just bought a new 2017 model yari with 160mm travel, installed it december and have ridden it maybe 4hours.

Today when i was about to go for a ride, it completely sucked itself in.

Tried yanking it as hard as i can, all sweaty already but its not giving in. Any other tips, or do i need to remove lower legs and the airshaft?

Hi. I have a 2018 yari rc. When the sucked-in happens, I do one of @eicca 's suggestions with a little improvisation and it works. Thanks, @eicca!

1. I pumped it to below max pressure.
2. Instead of yanking suggested by @eicca, I simply lift the front end with wheel installed about a foot or two off the floor & drop it.
3. Repeat step 2 a few times.
4. Remove the air pressure down to my sag pressure.

May or may not work for you. Fingers crossed.

Posted: Aug 21, 2019 at 14:05 Quote
So I bought a supposedly "NEW take off" 2019 Yari RC 150mm 29er fork off ebay. After having it installed by my lbs we realized it would not fully extend to full travel. The air shaft was really dirty when we removed the lowers, hence the "supposedly "NEW take off". My lbs cleaned out the air shaft and regreased it showing me the knotch where the negative air is released. We then upgraded the air shaft from 150mm to 160mm but the fork was still getting stuck around 15%-20% marker after compressing the fork. I decided to let it slide since I run my forks pretty stiff at 20%-25% sag.

On the first ride the fork felt skiddish and the noise was worst. All I heard the whole ride was a clunking noise when I went through chattery or rooty sections. After I got home I found this thread and decided to try out the suggestions from @eicca. None of them worked alone but after 3 hours I was able to get the fork to return to full travel with some extra steps. Thank you @eicca for your suggestions.

1. I left the fork pressure at my preferred PSI which is 100-105 PSI and did not change my rebound setting.
2. I pulled the fork up to fully extend the travel and turned the compression damper to full lockout.
3. Next I removed the front wheel and replaced the thru axle so that I had an anchor to put my foot on when I needed to pull up.
4. I then deflated all the air from the air shaft and removed the air cap. With the fork locked out, it didn't compress all the way down which it did originally meaning there was negative air trapped in the air shaft.
5. put your foot on the fork axle and pull up until you hear the air release from the air shaft. When done correctly your fork will be fully extended.
6. place the air cap back on and attach your shock pump.
7. compress the fork as far as you can go while holding down the air release on the shock pump. Once fully compressed and you feel like there is no more air in the fork release the air release button. The fork will then extend naturally due to the damper being locked out. You may see some fluid coming out from the seals around the stanchions at the top of the fork. Not sure if this is bad but it wasn't very much.
8. pump your fork up to over 100 PSI. This is a little scary since it over extended my fork travel to 180mm instead of the 160mm.
9. put your front tire back on.
10. Ride around with the fork fully lockout over little bumps like the lip on your driveway
11. now fully open the dampener on the fork and hop off a curb fully compressing the fork by putting all your weight down on the pedals, not the fork.
12. Release air from the fork to your desired PSI

My fork now returns to full travel (there may be less than 5% sag) after being compressed. The clunky noise however has not been solved. I read on another thread the internals are cheap and need to be upgraded to make it quiet. I will provide an update when I replace the stock motion control dampener to an RCT3 or RC2 dampener.

Posted: Aug 21, 2019 at 19:59 Quote
Removing the lowers and lubing can help too.

Posted: Aug 29, 2019 at 23:36 Quote
Removing lowers was the solution for me when i had this problem last winter.

Too much grease in neg pos port and it was clogged. Removed the extra grease and the for has worked like a charm after that.

Posted: Sep 4, 2019 at 20:12 Quote
for anyone else having this issue i went with a suggestion from freestyIAM in another thread and it worked great:

"Usually when i think of burping lowers its because of the opposite problem, pressurized lowers as air gets trapped behind the seals, but i this case i think the opposite may be happening. You've got a vaccum in your lowers. If you started your repressurization after the fork mod with the fork all the way compressed then maybe you've created a vaccum. I'd recommend depressurizing the fork completely and cycling to make sure the - air chamber is also depressurized, then stick zip ties in the seals of both legs and leave them in during your repressurization."

Posted: Jun 13, 2020 at 16:13 Quote
eicca wrote:
Yes. This infamous problem. I went through this with my Pike so hopefully my experience can help you out.

When operating properly, the fork will have "free play" at the top of its travel. You should be able to move it through the first 3-5% of its travel in both directions without any spring force.

How to test if the negative spring port is clogged: let all the air out. If it sucks itself down, the port is clogged with grease and not letting the air out of the negative spring. If the fork stays up with no air (aside from weight or pushing down on it) then it's working properly.

There are two ways to go about unclogging it. Number one, take off the air cap so you can see down inside. Pull up super hard. You should hear a small slurp from inside whenever it hits the top of its travel if air is passing through the port properly.

In my case, the fork was pulling itself down even with the air cap off. I pulled up hard a few times and nothing happened for a bit, and then on one good hard yank it made a nice loud sucking noise and stayed at the top of its travel like it should. Haven't had a problem since.

The other method is to pump the fork up to just below its max rating, whatever that is... Then pound it super hard a few times. You could also try pumping it up in intervals like you suggested.

but where is the port that needs to be unclogged?

Posted: Jun 23, 2020 at 23:51 Quote
[Quote="DylanZ91"
but where is the port that needs to be unclogged?[/Quote]
After removing the air shaft, looking up the inside of the upper, nearer the bottom there's a notch on the inside of the tube.

Just got some 2021 SIDs and had the trapped negative problem. Sat on the wheel and still couldn't pull it up anywhere near far enough. What worked on mine:
1. pumping them up just enough so they reached max extension
2. let a bit of air out until they started to get sucked down
3. sat on the wheel and extended them by push the bars up
4. cycled the travel a few times (they'd return to max ext)
5. repeated steps 2 - 4 until the neg was at near atmospheric

Posted: Jun 24, 2020 at 0:39 Quote
Just fitted the new debonair seal head upgrade that was designed to sort this problem on forks with debonair and has eliminated this problem on my Lyriks. Where I always had 10mm of lost travel, the fork always sits and returns to full travel now. Does exactly what it says on the tin

Posted: Sep 11, 2021 at 13:39 Quote
eicca wrote:
Yes. This infamous problem. I went through this with my Pike so hopefully my experience can help you out.

When operating properly, the fork will have "free play" at the top of its travel. You should be able to move it through the first 3-5% of its travel in both directions without any spring force.

How to test if the negative spring port is clogged: let all the air out. If it sucks itself down, the port is clogged with grease and not letting the air out of the negative spring. If the fork stays up with no air (aside from weight or pushing down on it) then it's working properly.

There are two ways to go about unclogging it. Number one, take off the air cap so you can see down inside. Pull up super hard. You should hear a small slurp from inside whenever it hits the top of its travel if air is passing through the port properly.

In my case, the fork was pulling itself down even with the air cap off. I pulled up hard a few times and nothing happened for a bit, and then on one good hard yank it made a nice loud sucking noise and stayed at the top of its travel like it should. Haven't had a problem since.

The other method is to pump the fork up to just below its max rating, whatever that is... Then pound it super hard a few times. You could also try pumping it up in intervals like you suggested.


You’re a god!!
2020 lyriks and still having this problem

Just for the people who need to do this just to clarify you need to take the valve core completely out of the schrader valve, turn the bike upside down stand on the handlebars and pull up on the fork lowers until you hear that slurp

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