Skylark Posted February 10, 2014 Share On my Rockshox Revelation(2009 Rockshox Revelation 426 140mm with Motion control) I'm not getting full travel, bottoms out with a solid thud with 25mm of travel left. I let out all the air from both positive and negative and still won't go past the last 25mm of travel. What could be the problem? I'm thinking the last time I serviced the lowers I used to much oil?Or apparently on the damper side I may have a damping fluid leak into the lowers which is doing the same thing as overfilling the lowers oil. Only think I have done recently is I screwed out the damper cartridge and then put it back in, could that have somehow done anything? Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted February 10, 2014 Share PM Droo... droo 1 Link to comment Share on other sites More sharing options...
Goosebay Posted February 10, 2014 Share On my Rockshox Revelation(2009 Rockshox Revelation 426 140mm with Motion control) I'm not getting full travel, bottoms out with a solid thud with 25mm of travel left. I let out all the air from both positive and negative and still won't go past the last 25mm of travel. What could be the problem? I'm thinking the last time I serviced the lowers I used to much oil?Or apparently on the damper side I may have a damping fluid leak into the lowers which is doing the same thing as overfilling the lowers oil. Only think I have done recently is I screwed out the damper cartridge and then put it back in, could that have somehow done anything? Probably oil from the damper leaking into the lowers if the problem wasn't always there. Pour out the oil from the damper leg and see how much is there, if quite a bit less than what it should be then loosen the damper piston shaft and see how much oil is in the lowers. But does sound like hydraulic lock due to too much oil in the lowers. RockCoach and droo 2 Link to comment Share on other sites More sharing options...
droo Posted February 10, 2014 Share Yup, my money's on hydraulic lock too. Service as per the instructions on the SRAM website, or send it to me and I'll sort it out for you. If you need help or supplies you know where to find me... there are also a few threads about oils and greases and the like in the tech forums. Link to comment Share on other sites More sharing options...
Skylark Posted February 10, 2014 Share If the damper was leaking oil into the lowers to the degree that I now have hydraulic lock wouldn't my fork be like a pogo stick? All seems fine apart from the hydraulic lock, honestly can't remember when it started but I road through an innocuous looking puddle at speed over the weekend only to find it was half a foot deep, only then I noticed the thud with 25mm of travel left, so it was quite an extreme situation but it brought to light the issue. If I open up the lowers how can I check to see if the damper is leaking fluid? Link to comment Share on other sites More sharing options...
Goosebay Posted February 10, 2014 Share If the damper was leaking oil into the lowers to the degree that I now have hydraulic lock wouldn't my fork be like a pogo stick? All seems fine apart from the hydraulic lock, honestly can't remember when it started but I road through an innocuous looking puddle at speed over the weekend only to find it was half a foot deep, only then I noticed the thud with 25mm of travel left, so it was quite an extreme situation but it brought to light the issue. If I open up the lowers how can I check to see if the damper is leaking fluid? Your rebound will still function to a degree because not all the oil has leaked through. The amount of oil coming out the lower will give you a clue. You should only have about 15ml in the botom. Link to comment Share on other sites More sharing options...
droo Posted February 10, 2014 Share Your rebound will still function to a degree because not all the oil has leaked through. The amount of oil coming out the lower will give you a clue. You should only have about 15ml in the botom. Try 5ml in RS forks... Step one would be to take the compression damper out of the right leg and measure the oil height. If it's lower than 10mm above the top of the foot of the compression damper, you have a winner. Then knock the lowers off and see how much oil is in there. Anything more than 5ml and you've confirmed the issue. As far as the pogo stick goes, that'll only happen if there's no oil left in the damper - the rebound piston sits at the bottom of the damper, so at the very least the ending stroke rebound will still function even if the oil is low. The first thing you'll notice is that your lockout or low speed compression stops working. Link to comment Share on other sites More sharing options...
Goosebay Posted February 10, 2014 Share Try 5ml in RS forks... Step one would be to take the compression damper out of the right leg and measure the oil height. If it's lower than 10mm above the top of the foot of the compression damper, you have a winner. Then knock the lowers off and see how much oil is in there. Anything more than 5ml and you've confirmed the issue. As far as the pogo stick goes, that'll only happen if there's no oil left in the damper - the rebound piston sits at the bottom of the damper, so at the very least the ending stroke rebound will still function even if the oil is low. The first thing you'll notice is that your lockout or low speed compression stops working. Maybe, but a lot of guys put in 15ml due to RS data, I generally measure the oil that comes out, and has always been more than 5ml. I know you guys are experts in this field, so would appreciate just a bit of know how here of why I should put in 5ml. Is that only on the longer travel forks? My revelation is due for a service fairly soon. Link to comment Share on other sites More sharing options...
droo Posted February 11, 2014 Share Maybe, but a lot of guys put in 15ml due to RS data, I generally measure the oil that comes out, and has always been more than 5ml. I know you guys are experts in this field, so would appreciate just a bit of know how here of why I should put in 5ml. Is that only on the longer travel forks? My revelation is due for a service fairly soon. The only reason that you'll find 15ml in there is because whoever serviced the fork last read the data sheet wrong. I'm not sure why they spec so little - Fox specs 20 - 30ml each side - but it seems to work. I know Magura forks only use 2ml per side, but that's because the oil seals aren't the best at keeping oil in and anything more than 2ml just leaks out. Link to comment Share on other sites More sharing options...
Goosebay Posted February 11, 2014 Share The only reason that you'll find 15ml in there is because whoever serviced the fork last read the data sheet wrong. I'm not sure why they spec so little - Fox specs 20 - 30ml each side - but it seems to work. I know Magura forks only use 2ml per side, but that's because the oil seals aren't the best at keeping oil in and anything more than 2ml just leaks out. I've just checked my manual - they definitely spec 15ml right leg and 6ml left leg Link to comment Share on other sites More sharing options...
droo Posted February 11, 2014 Share I've just checked my manual - they definitely spec 15ml right leg and 6ml left leg Year and model? Link to comment Share on other sites More sharing options...
Goosebay Posted February 11, 2014 Share Year and model? 2007? 120-150 dual air Link to comment Share on other sites More sharing options...
droo Posted February 11, 2014 Share 2007? 120-150 dual air Then you're right. Since 2009 they've only been using 5cc 15wt per leg, but the way they've got it set out on the table it's often misread. Link to comment Share on other sites More sharing options...
Goosebay Posted February 11, 2014 Share Then you're right. Since 2009 they've only been using 5cc 15wt per leg, but the way they've got it set out on the table it's often misread.Thanks for the info, would have made the incorrect assumption with a newer fork! Link to comment Share on other sites More sharing options...
Skylark Posted February 12, 2014 Share I just checked the RS official manual I used to service my 2009 lowers and they say 15ml in my fork.As does this breakdown of a lowers service on a virtually identical fork to mine:http://www.bikeradar.com/mtb/gear/article/workshop-rockshox-revelation-lower-leg-service-24649/ In the RS official 2009 service manual most forks use 10-15ml in the lowers, some 20ml and up to 30ml in some. The SID was the only fork that uses 5ml. Droo what gives? Link to comment Share on other sites More sharing options...
Brian Fantana Posted February 12, 2014 Share The 2012 manual says 5-8ml Link to comment Share on other sites More sharing options...
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