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To stiffen up non adjustable front forks

Discussion in 'Maintenance and Servicing' started by AdamA, May 6, 2016.

  1. I have a Ninja 300 that has un-adjustable front forks but they are wayyy to floaty for my liking.
    I've heard you can put in a thicker fork oil as an alternate way to indirectly cause more compression.

    Is this possible and advisable?

  2. is the sag correct for you?

    you can make and put in a longer fork spring spacer to set the sag/slightly stiffen spring rate.
    can also put in thicker oil, but I don't think you want the oil to be doing all the work.

    sorta like this, but not with the bodgy PVC method...

    anyway, figure out how much sag you need to correct first. that will give you spacer length
    or get adjustable spacer, like these Slingshot Racing : Kawasaki 08 09 10 11 Ninja 250R Billet CNC Preload Adjusters - $99.99
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  3. When I had my gpx250 I used the "two-bob fix". You just use 20c pieces (two-bob in my Dad's parlance ) as spacers to add more preload. If your forks are too big for 20c you could use 50c pieces. If the sag is right but you find the suspension too bouncy, then you'd consider a grade heavier fork oil.
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  4. also amount of oil to change the air spring portion at the end of travel
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  5. Stainless washers are better,just make sure they sit against where the spring and standard spacer sit. Don't go nuts,if you add to many it gets hard to start the tread on the fork cap. Damage this tread and start looking for a rope and a tree. What do you weigh, if you are under 90kg a bit more preload will work,if you over that then heavier weight springs are a much better fix. I like that preload gadget above BTW. Have you done the cable tie trick, add a cable tie tight to the fork leg, as high as possible then sit normally on the bike. Get off and jack the bike off the ground and measure how much travel the bike uses with just you on it. This should be 30% of total travel or 30 to 40mm on your average roady. This is important to more than the suspension, more sag slows the steering, less speeds it up. The rear should be done as well.
    • Like Like x 2
  6. Thanks guys I'll look into adding in some spacers and thicker grade of oil.