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St4s Front Fork Rebuild

Discussion in 'Sport Touring' started by Turbogeek, Jan 14, 2020.

  1. I've had a search on the forum and on the 'net in general, but can't find what I'm looking for, so here goes....

    This past weekend I stripped and rebuilt the front forks on my 4s, with new seals, bushes and oil.
    The bike is registered as a ST4S-02, on a 2003 53-plate.

    I have a couple of questions as I have found conflicting information in the various versions of the service manual floating around online.

    The manual I used stated that the oil quantity/level was 536cc/104mm, which is what I've used, but I've seen another that states 492cc/94mm is correct.

    Also, on the fork cap preload adjusters, the service manual states that the top of the preload adjuster cap (where the rebound adjuster lives) should be between 10mm and 22mm protrusion from the fork cap itself. When I adjust the preload caps so they are just starting to add compression to the spring, they are at 0mm protrusion (both sides, so if I have made a mistake one side, I've done the same the other side).

    Does anyone have a definitive set of figures?
     
  2. Edit for being too stupid to read the manual properly for the preload:-
    upload_2020-1-14_19-59-31.png
    Read it again and understood what was wrong.
    Now properly set to 16mm as per the manual. Would have been a 5 min job except for dropping one of the handlebar bolts down into the engine room. A titanium magnet would have been very handy just now......

    Anyone got anything definitive for the fork oil level?
     
  3. 104mm rings a bell.... if no one else chips in, I can check for you tomorrow
     
  4. Thankyou @nelly , that would be perfect. It's what I've used so here's hoping!
     
  5. Had a check this morning. The manual states 108mm. Looking at the two sets of figures you have, they contradict each other. The higher quantity of 536 would reduce the air gap, yet the other set has a lower quantity of oil but with a smaller air gap. I always build off air gap wherever possible.
    If you have 104mm, I'd stick with that. 4mm is neither here nor there and would probably increase a little as the forks work all the air out of the damper.
    You're good to go.... Enjoy her :)
     
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  6. Thankyou so much for your help!
     
  7. Hi Neil!

    Good too see providing the ace advice I always remebered :)

    #Turbogeek RaceTech gold valves are a nice ride improvement for next time.

    Cheers
     
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  8. beware the ST4s manual was a cut and paste job from the ST4 and has many errors... EG Drive train figures
     
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