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Leaking fork oil

Discussion in 'Maintenance and Servicing' started by nedlud, Sep 28, 2015.

  1. Hi there,
    I didn't ride my CB900 much over winter, but I took it out for a decent day of riding recently and it seemed fine.
    But yesterday I noticed a large puddle of oil under the front wheel and it looks like it's come from the front forks (right hand side only, I think).
    So my question is: How hard is this to fix by myself (not being very mechanical)?
    And/or, how safe is it to ride to the shop and get it fixed?

  2. Could be the seal, could be some grit which got in there which might be able to be cleaned with a seal mate type tool. Be sure to check the stanchions for any nicks or scratches too.

    Basically you need to jack the bike up, slide the forks out of the triple clamps and undot a nut on top and allen bolt on the bottom then everything in the forks slide out in order (including the fluid). It's not much more work than replacing the fluid which should be done every couple of years. You also get to check out how worn the bushings are too.

    Check out youtube for some guides - Delboys Garage has a great one which helped me immensely.

    Only special tool you might need are seal drivers. You can make one up in a few minutes with some pvc pipe or wrap some electrical tape around the stanchion to get the same result though.

    If you want to ride it its not a problem as long as you dont see any chance of oil spilling onto the front tyre or brake rotor.
  3. Replacing the fork seals is not hard if you take it slowly and carefully. It's time consuming, though, and it's not really a beginner's task. It requires some preparation, too.

    You will need to get the front wheel off the ground. If your CB900 has a center stand, you can do this by strapping a lot of weight to pillion seat. If not, then you need to get the back on a stand and figure out some way to raise the front too by something other than the forks. I used to hang bikes from the garage roof via their handlebars for this purpose.

    As Harb said, you need a fork seal driver or equivalent. You can make one with some appropriately sized PVC pipe and a hacksaw.

    You might be able to get away with a Sealmate, but in my experience, for road bikes they're a temporary solution at best, especially if your fork is pissing out oil to the extent that it's pooling on the ground underneath. How old is the CB900? Those seals have probably had their day.

  4. There ya go.
  5. Thanks for the feedback everyone.

    I had a closer look at the current seals and they are visibly perished with little cracks all around. I guess that's not so surprising given that it's a 2007.

    I cleaned up all the leaked oil, and there was some oil on the front disks, but the brake pads/calipers seem untouched. I cleaned the disks carefully and will try riding the bike to the mechanics later this week. I'm definitely a beginner at the bike repair stuff and I'd much rather get somebody to fix this for me.

  6. This is a very clear and concise DIY video. I will be inspecting and changing my fork seals and/or forks this weekend. Thanks guys!