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Soft front suspension

Discussion in 'Technical and Troubleshooting Torque' started by Tails, Feb 17, 2008.

  1. I'm new to the bike scene, been playing with cars for around 20yrs, nad have recently bought an FZR250 for my girl friend to learn on. It needs a little bit of work most I can do no problems but I've never had to fix soft fork suspension.

    The seals aren't leaking so can someone help me out? Does it possibly just need more fork oil is there possibly something deeper?

  2. Replace seals and put in stiffer springs or at least new oil. Being a very old bike its likely it needs doing very very badly, and chances are its been neglected by previous p platers.
  3. Use heavier fork oil... Maybe 15w?
  4. 1) I assume you mean that the forks have sagged - with no rider or with the rider on they are using half of their travel? Or maybe when you push them they bottom?

    If so, new springs will be the answer. Preloading them will probably not work because either the spring has lost its tension or was never strong enough in the first place. You also need to calculate whether the preload spacer will over compress the springs so that they become coil-bound.

    2) If they are too bouncy that is due to a lack of damping, which is provided by oil in the fork. This can/should be replaced. It could easily have the original fish oil that the J factories seem to have used for decades. Try 15w fork oil, but you need to find the correct amount. Too much and you could hydraulic lock, or just blow the fork seals


    Trevor G
  5. Ja and for reference, new aftermarket springs tailored to your weight are about $200. New fork oil is about $15. Replacing either oil, or springs, or both, will take a first-timer about 3-4 hours or a reasonable backyard spannerman about 2.

    Trev's right, the springs are likely pretty rooted, being as old as I suspect they are, but if you don't have 200 squids to throw around, you might find that going to a 15W or 20W fork oil makes enough of a difference to make it much more rideable. Even just refreshing the oil will help; lots of bikes go their whole lives without the suspension getting serviced.
  6. Thanks for the replies.

    The bike hasn't lost any height, it just compresses really easily and kind of bounces when released.
  7. then you are in luck.

    do these bikes have any damping adjustment? If so wind it up.

    Replace the fork oil either way. It does get pretty thin with age. It's a cheap and easy job.
  8. In that case just change the oil. Use at least 15w fork oil. You will need to find the correct amount for each leg to avoid other problems.


    Trevor G