1. Husqvarna Motorcycles Made In Sweden - About 1988 and older

XC 430 front Forks damper rods

Discussion in 'Vintage Restoration Projects' started by shunter17, Jan 2, 2012.

  1. shunter17 Husqvarna
    AA Class

    Hi' im new to the forum, i'm currently doing up a 1981 XC430 and i'm having trouble with the front forks. topping out with a clank metal to metal.
    I originally took them to bits to drop in new fork seals as they where leaking oil.
    I have dropped the new seals in and filled with 10W oil 6 inch from top when fully compressed and they work a treat.
    However one of the fork comes back at top of the stroke with a huge clank !!!.
    Having taken them to bits aagin i found that one of the forks has a metal bush at the top of the damper rod (this is the one that clanks) and the other does not (does not clank).
    Questions: what grade oil should i be using, have i filled up to correct level and finally and the most important question, should the damper rod have a top out spring or a washer/bush on top of the rod where it is 1mm wider and if so i'm guessing both forks should be the same in each fork ?
    Any advice would be greatly welcomed
  2. Michel Dufayard Husqvarna
    Pro Class

    Location:
    France
    Isn't the plastic washer at the top of your damping spindle out of order ?
  3. adam6402 Husqvarna
    AA Class

    Location:
    Tulsa, OK
    Husqvarna Motorcycle:
    None
    I just happen to be taking my 250XC forks apart for cleaning and new seals. Your forks are the same as mine. Your damper rod should have a damper rod seal/washer (one shown installed and the other off the other daming rod). The other metal piece shown on the damper rod is the "Bottom Valve" that is held in place at the bottom of the upper fork leg with a circlip. When the fork is fully extended the "bottom valve" makes contact with the ridge on the damper rod. When bottoming out the upper fork tube will hit the large washer pictured that sits at the bottom of the lower fork leg.

    I can't speak to oil just yet as while I've had the bike for awhile, due to work and relocation finally just getting around to doing some refurbishment. I plan on starting with 10w fork specific oil 5.5 inches from top (compressed and springs out).

    Hope that helps.
    IMG00569-20120104-2043.jpg
  4. shunter17 Husqvarna
    AA Class

    Thanks Adam for the information.
    I'm going to take them apart again this weekend, i will take some photographs and place them on the forum. For what ever reason i dont think the inners of my forks look like yours. Although the concept is the same i'm wondering if someone has at sometime introduced a different damper rod at some time. your forks look like the parts manual i have, but for what ever reason mine look a little different unless i'm being stupid. Would appreciate any advice again after i have posted the pictures over the weekend.
    many thanks
    Steve.
  5. shunter17 Husqvarna
    AA Class

    Micheal, i will post some pictures of my forks over the weekend, when i take apart again. I dont think i have a plastic washer, which is a little concerning !!!
  6. Bengt Husky Husqvarna
    AA Class

    Location:
    UK
    i think these forks are the same as on my '83 430. I had the same issues with the clanking noise. I found the damping rod had picked up on the damping valve. I cleaned the rod up, put in new seals and up the weight of the oil to 15Wt (I'm 105Kg) and the noise went away. I'm in the process of doing a complete re-build at the moment and I'm going to put 1" spacers in the top to compress the springs a bit more. I might try 20Wt oil as well as I like the front end to be really stiff when I ride.
  7. adam6402 Husqvarna
    AA Class

    Location:
    Tulsa, OK
    Husqvarna Motorcycle:
    None
    Here's a couple of CH threads that you might find helpful as well.

    http://www.cafehusky.com/threads/fork-seal-snap-ring-for-40mm-fork.12137/#post-115808
    http://www.cafehusky.com/threads/1983-40mm-forks.9777/#post-98751

    Its no wonder so many dirt bikes ended up junked, people just never did maintenance or they tried to do it themselves and got it wrong. On the forks I took apart last night, obviously someone tried to use a screwdriver to pry the seals out. When I removed the lower leg drain plug, it ran muddy oil and goop.

    Not sure that I wanted to reuse the damper rods due to damage, so I took apart the forks off my parts bike. After removing the top cap, I noticed a strong smell of 90w gear oil. I pulled the drain plug and a little goop came out and them stopped as it was plugged. I pulled the damper rod bolt and more goop came out in clumps before oil started running. The good news is the fork tubes and damper rods look better than what came out of my bike.

    I must say, this is fun, going to be a good year!
    Adam
  8. shunter17 Husqvarna
    AA Class

    Hi i believe the forks on my 1981 XC may be a little later than the bike , i'm going to take apart again at the weekend and drop some picture on the forum. The problemn i have is the forks clanking at the top out position. Which suggests i need a top out spring/washer or maybe just thinker oil.
  9. shunter17 Husqvarna
    AA Class

    Thanks Adam for the links. My fork oil also left a little to be desired when drained. i will drop pictures on Forum saturday night UK time !!
  10. shunter17 Husqvarna
    AA Class

    damper1.jpg damper2.jpg damper1.jpg

    Attached Files:

  11. shunter17 Husqvarna
    AA Class

    Hi thanks for all the responses i have had regarding the forks topping out with a clank. I took the offending fork to bits again today and have posted pictures above.
    If anybody can tell me the year of the forks that would be great, as although they look correct on an 1981 xc430 i'm think they could be 84/85!!

    I have i think got to the bottom of the problem. if you look at the second picture the left most metal piece seats the damper rod and is screwed to the bottom of the fork. The second collar sits inside the 3rd collar which you can see slotted together on the last picture and is held into the bottom of the fork leg with a cir-clip. This then moves up and down the fork with the leg. You will see a taper washer in between these two collars that fell out of the forks when i removed the damper rod. I had assumed that this tapered washer at the top of the underside of the damper rod as shown in picture 1 and 3 as it slid on perfect. However it appears it dropped out between collars 1 and 2 and acts as some sort of valve. When i placed in taper side up back between the two collars and cir-cliped the whole thing back into the bottom of the fork leg it all appears to work OK.

    I also think i didn't work the forks enough with my hand over the top of the Legs when i first filled them with Oil, making sure the oil got sucked down into the bottom of the leg. As this time i manages to get approx 420 ml of oil in when fully compressed, which brought the oil 6 inch from the top. So i think for my bulk of 95kg and 6ft 2 i should be OK to roll.

    I will post some pics of bike when fully restored in next couple of weeks.
    Cheers
    Steve.
  12. ronn450 Husqvarna
    AA Class

    Location:
    Yakima
    Your forks are 81-82 and use a blend of 5wt and 10wt fork oil and replace the springs for your weight and yes you should have plastic washers also , Take Care , Ron
  13. adam6402 Husqvarna
    AA Class

    Location:
    Tulsa, OK
    Husqvarna Motorcycle:
    None
    The lower fork legs look like 81-84, but that's it. Whatever that is in the pictures, it's custom/after market stuff. Take a look at this thread below about half way down on page 8, it shows close up pictures of all parts that go into stock forks. Do you get the full 12 inches of travel out of these forks? Hopefully someone more knowlegable than I can tell you what exactly you have. Good luck!

    http://www.cafehusky.com/threads/19...ion-inspiration-action.1173/page-8#post-23186