2006 250x Fork Dampener Doesn't return all the way
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    by JimDirt » Wed Jul 08, 2015 10:29 am

    Well if you ride a lot you "should" change the oil every season (at least in the forks , the shock can usually go twice as long because its less prone to dirt than the forks) , but when you do them then , maybe don't push them fully in , i believe the manual says to only push them in 100mm or 3.9 inches when pumping them , i think your (as i mentioned before in your post) , pushing the rebound stack out of the oil and getting air back in , then when you go to pump them again , they will not extend fully ....its the only thing i can think of your doing wrong , it has to be in the bleeding process , same goes here for the OP
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Wed Jul 08, 2015 11:06 am

    The manual says to do several slow pumps to 3.9", which I am doing. The rods extended fully afterwards. It is the following step (full stroke compression) that is causing the problem. If this last step isn't performed, then too much fluid will remain in the fork. I know this because I got exactly the amount specified in the manual after doing a full compression (175cc). If I didn't do the full compression, there would be about 17cc too much remaining. Note the procedure says to compress the fork to "full stroke".

    Image
    2007 CRF250X
    2004 CRF230F (sold)
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    by JimDirt » Wed Jul 08, 2015 11:33 am

    Yes , and when you go to 13-23 in the manual , it says that you hold it level and compress the rod , and it should extend to Maximum Length on its own , then if it does not then re-bleed the damper again

    That is the important part ! , and most likely what is the issue , its something going wrong in the bleeding process , i know when you do it and it works you will have figured out what you did wrong , and then you will notice a difference in how much better the suspension works , compared to now , but the bleeding procedure is the most important part of the process by far
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Wed Jul 08, 2015 11:50 am

    I bled the forks until no more bubbles were present in the fluid. I tilted them this way and that, tapped the tube to coax bubbles out, slowly pumped the rod at least 100 times, topped the chamber off with the exact amount of fluid, sometimes more just to be safe, slowly inserted the pistons allowing air to pass by as I inserted them, kept pressure on the piston while tightening the cap.

    If we don't follow the last step by not compressing fully, then there will be too much fluid remaining in the cartridge, which will be expelled the first time the fork bottoms out while riding, which will result in too much oil in the outer chamber. Am I right? When is the next time you will be changing your fluid? I would like to see what happens with yours after a FULL stroke.
    2007 CRF250X
    2004 CRF230F (sold)
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Wed Jul 08, 2015 12:03 pm

    Does the compression clicker need to be in a certain position when inserting the piston? And does it matter whether the bleed screw is installed or not (I left mine out)? I just read a post by somebody on TT that said to have the clicker fully soft (CCW) when inserting the piston, then position it so it is two or three clicks out, then tap the top of the fork with a rubber mallet to expel any trapped air.
    2007 CRF250X
    2004 CRF230F (sold)
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    by JimDirt » Wed Jul 08, 2015 1:56 pm

    When your inserting the Cap Assembly, you push it in real slow , when it goes in , it will push it all out except what needs to be in there , if you go too fast it will blow out extra and you will have air in the closed system just like if you went real fast with your hand in the water , it blows the fluid out of the way, if you have way too much in the cartridge , the cap assembly will not go in at all , it will Hydro-Lock as you get to the last bit before the threads touch , the Free Piston Seal and the O-Rings are what seal the system , so if you do it correctly , no fluid after the O-Ring seats will get out as it is what is last to close off the system

    As far as mine after a full stroke , the only time mine have not fully extended is when the Free Piston Seal is bad , otherwise , every time , they fully extend , its been this way since i started doing Twin Chamber suspension , over 10 years ago

    As far as the clickers go , they should be fully OUT/Soft , when installing , you dont set them till the cap is installed and tightened down ready to go back on the bike , then i adjust the compression , then flip the forks over and adjust the rebound adjusters , as they BOTH should be fully soft when installing , and i always have the air bleed screw installed (the stock screw)before i put the fork cap in the cartridge , after i have everything mounted back in the clamps , then i unscrew the bleeder screw and install my push button bleeders , , then after the wheel is back on , and the bike is ready to ride , i pump the forks as hard as i can by pushing down on the bike several times , then get the bike back up on the stand and push the bleeders , then i am done and ready to ride , you don't need a pristine workshop environment to do this either , i have done this on the back of my open trailer , at the track , when changing around stacks , and the rod always fully extends , that is how i have done it for as long as i can remember (doing it at the track i only do occasionally if i don't like how the valving works right after i change the valving around and i can't adjust the issue out of it)

    But since the last time i redid the valving (just this spring) , i really like the way the bike works both off road and at the track , i have yet to adjust a clicker from when i installed everything , its that good (this is on both bikes) , i wont be taking the bikes apart till this winter after the snow hits , so most likely December , as i usually can still get some riding in , in November , and October i am mostly hunting , so i dont ride much if at all in October

    About the only adjustment i may have to do this year , is IF i end up going to Washougal this year , and doing the PRO race (Pacific Racing Organization) in September for the Top Gun MX Team Shootout Race with my friend in Washington (state) as its a faster longer track and i will have to stiffen it up for the bigger jumps and faster speeds , as some of the speeds get around 70mph when your hitting stuff , so too soft and you will G out and be on the ground
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Thu Jul 09, 2015 10:38 am

    Other than leaving the bleeder screws in, I am doing everything just as you say. I believe the manual says to remove the bleeders, but can't say for sure. I wouldn't think that would affect anything (would it?) since there are two large bleed holes in the side of the cartridge.
    2007 CRF250X
    2004 CRF230F (sold)
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    by JimDirt » Thu Jul 09, 2015 12:58 pm

    Just for the heck of it , on the next tear down , try letting for forks sit overnight after your done "bleeding" and before assembling the cartridge , , wait for a hour or so and go push/pull the rod and see if there are any bubbles , look VERY closely and make sure that there is not even 1 miniscule bubble , if there is let it sit over night , then in the morning , pull and push the rod a few times and see if there is any bubbles , i still believe you are not getting all the air out , if the Free Piston Seal and Rebound Rod Seal are not leaking (Rebound rod seal would have oil running down the rod) , then it has to be a air still in the chamber issue , adding slightly too much oil is better than not adding enough , so go a little on the heavy side before installing the cap assembly , there is no other explanation that i can think of besides its getting or still has air in it :?

    Keep in mind , i am not a Race Tech , or any other suspension company "tech" , i am just a old mechanic that took on learning suspension on my own , i am far from a "expert" , though i have learned a lot , and what i have learned i have no problem in sharing , there is still much i do not know , and just do not have a solid answer for , but from what i do know , this seems like air in the chamber in both cases (you and the OP)
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Thu Jul 09, 2015 1:51 pm

    Here's the response I received from the company I purchased the inner piston seals from:

    The drag (friction) on the cartridge rod slows down the rods return as it gets closer to full extension because the spring pressure is getting less and less.

    If would you like the cartridge rod to fulling return, when you perform the final bleed leave about 1 inch of the rod out of the body (the lock nut is a good point).

    In my professional opinion/experience completely compressing the rod into the cartridge body for the final bleed often over purges the cartridge oil volume.


    Sounds feasible to me. Since the main springs push the rods to their full extension, I think it's fine. There IS resistance when compressing the rods for that first inch, so even though they can't extend on their own, they ARE providing damping.
    2007 CRF250X
    2004 CRF230F (sold)
  • mossman77
    Posts: 316
    Joined: Tue Jan 13, 2015 9:28 am

    by mossman77 » Thu Jul 09, 2015 1:56 pm

    mossman77 wrote:Here's the response I received from the company I purchased the inner piston seals from:

    The drag (friction) on the cartridge rod slows down the rods return as it gets closer to full extension because the spring pressure is getting less and less.

    If would you like the cartridge rod to fulling return, when you perform the final bleed leave about 1 inch of the rod out of the body (the lock nut is a good point).

    In my professional opinion/experience completely compressing the rod into the cartridge body for the final bleed often over purges the cartridge oil volume.


    Sounds feasible to me. Since the main springs push the rods to their full extension, I think it's fine. There IS resistance when compressing the rods for that first inch, so even though they can't extend on their own, they ARE providing damping. However, once I am riding the bike and the forks compress fully, the same thing will happen. I think we've beaten this subject enough. I'm not going to worry about it anymore.
    2007 CRF250X
    2004 CRF230F (sold)
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    by JimDirt » Thu Jul 09, 2015 3:09 pm

    Yea , no problem , and i agree with the Tech , if you compress the rod completely , it will change the stroke because of how the oil disperses , however , i always compress with the locknut on , so i dont actually go to the end of the rod , in fact i leave about a inch from the nut when i stop , again , as long as its not sucking back in , then you should be ok , but if there is no air in the system and the cartridge is full of oil , it can't compress because fluid will only compress so far and it will just push after that point so it would have to extend all the way .... but yea , this horse is ready for the glue factory ;)

    Image
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho

Who is online

Users browsing this forum: Google [Bot] and 2 guests