Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Changing Fork Seals on Sat!!

Discussion in 'Bling and Appearance' at netrider.net.au started by Morbo28, Jun 13, 2008.

  1. Hi All! hi-103.

    Okay, after reading lots of threads on here and reading the manuals and watching the You Tube vids I am changing my fork seals on the NSR over the weekend! I wouldn't mind double checking a few things with you guys first though is that's cool...

    - Full kit (x2) is ready to be picked up

    - Wasn't sure on weight of fork oil to use. Couldn't find it in either of the manuals zen-reading-news. I asked PS and they said the original is 5W!!!! (a lot lighter than I thought) I already wanted to up it slightly to firm up the front end, so I think I might try 10W, do you think this is a good idea or should I stick to the 5W? (The rear suspension is not adjustable so I wonder if this will unbalance the handling)

    - Still haven't been able to solve the problem of how to seat the new seals correctly. I know there is a proper pipe tool thing to do it, but what method do other people use? or do you know where they sell the tool? PS said they did not sell it.

    Thanks for your help peeps.

  2. You can blend 5W with 10W to make 7.5W :) Just make sure it's the same brand, type etc etc. I have some fork oil in the shed, it is either 10W or 7.5W you're welcome to have if you want it.

    I haven't done forks myself, but would be interested in checking out how it is done.
  3. You should post this into the ride section and list it as a spanner day. Could get more interest and a few people who know what they are doing might come along (loz perhaps)
  4. I have used various pieces of PVC pipe sliced up one side as drivers. Works just fine.

    The other trick is having (or making) the tools to undo damper rods. I'm not familiar with the NSR's forks so can't clarify anything there.

    Fork oil weight and height are the only tuning you get in non-adjustable forks short of swapping springs and physically altering the valving, but again, not being familiar with the NSR I dunno what built in adjustment you have. Anyhow, my point is that you can do a lot of tuning with fork oils but any changes need to be recorded so that if you find it's better in some ways but worse in others you can work out which way to go next.

    Changes in oil height effect over all spring rate AND damping response. Changes there make your rear end behave differently too. Your weight and riding style make the waters muddier still. If had an "interesting" time working on the K100RS suspension, but I have gained a marked improvement in handling, but things are nowhere near as cushy and comfortable as before. Learned a lot too!

    There's a reason that suspension tuners are not cheap!
  5. Ya OK so here's what I reckon:

    10W oil is a MINIMUM. I use 20W on all my bikes, but I'm a fat bastard. I'd go 10 or 15 if I were you, you'll love the difference.

    When we were doing Nee's fork seals (im.on.it) he had found a bit of old tubing that we used to whack the old seals onto the new seals to seat them. It worked great. Drop him a PM or something, he might still have it around.


    You'll need a couple of old towels to lay everything out on once the fork is disassembled, otherwise oil goes everywhere. What else... The cartridge bit of the fork can be difficult to unscrew because you need to use the long end of the hex key to get to it, and it's hard to put torque on the other end. If you've got an extender and hex key bit in your socket set I reckon that's the way to go.

    Otherwise, this is actually quite a fun job on a simple pair of forks. Don't forget to lay the parts out IN ORDER every time you take something out. Do the washers go under or over the preload spacers? Which end of the spring points down? Which bit of the fork seal assembly goes in first etc - that can save you some head-scratching.

    Let us know if you want a hand, if I'm not busy I might be able to pop around for a look.
  6. Oh, and if you're chopping up PVC pipe to use as a seal driver, take care to clean all the shavings and dust and shit out of it before you get it anywhere near the fork seals - the last thing you want is to get grit in those.
  7. Thanks heaps everyone. :grin:

    Dammit - I just bought 7W :cry: I might exchange it from PS this arvo or early tomorrow morning, considering what you guys said. I figured the front end may have been extra squishy due to low oil level (quite a bit has come out) so I thought going up to 7W plus sealing everything up and proper amount of oil should sort things. But by the sounds of it I should go straight to 10W or 12.5W. Done.

    I just picked up the seals. I thought it was a full kit with circlips etc but it was just 2x oil seals and 2x dust seals. That'll do. Done.

    Okay, I might buy a short lentgh of PVC pipe to use as a basher so I have one for future use. I guess it'll need to have an Inside Diameter slightly larger than the inner fork tube and an OD slightly smaller than the outer fork tube. If that fails, I'll put the old seal on top and *gently* tap it in evenly with a rubber mallet and a screw driver. Done.

    Interestingly I noted on one website it said
    But it didn't explain any more about it than that. :? So maybe the rule is you get one third of the difference higher than the lower weight when you mix oils..

    Thanks for the offer Mekros, much appreciated. I'll just switch the oil over at the shop sionce I bought some :)

    People mentioned a spanner day. I could do that if people were keen, it might also mean some more experienced people might come. I wonder if tomorrow is too early for people? I suppose I could do it on Wed night if people would prefer.
  8.  Top
  9. :WStupid: