Fork Oil Level

4 replies to this topic
  • Kirtwell

Posted February 19, 2002 - 09:59 AM


Hey guys,
I blew my fork seals and decided to replace them this last weekend. Well, I was looking in my 01' 426 owners manual and saw the tolerance for oil level was 80-130mm from the top. The last time I changed the oil I went right in the middle...actually I went 100mm from the top.
The result was I kept bottoming my forks out on easy landings.
So, this weekend I went with the spec's on Racetech. It said I needed 90mm from the top.
That's what I did. I put everthing back together and HOLY ShEET those forks were stiff....I can barely push them down sitting on the bike and holding the front brake.....

Is that normal? Has anyone ever put that much oil in their forks? Do I need to revalve?

BTW: I'm 225 lbs in case anyone asks.

  • h_bomb

Posted February 19, 2002 - 12:01 PM


Race Tech did my 2002 I weigh 200lbs they used stk springs .46f 5.4r and revalve set my forks at 90mm It felt kinda harsh at first but after a few big hits it started getting softer Im about an inch away from bottoming out and thats over shooting flat landing I might try softening the compression a couple clicks.I would keep it at 90mm and soften with clickers. :) :D

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • bassr_#186

Posted February 19, 2002 - 12:20 PM


I am not a suspension expert, but I don't think increasing the oil height should increase fork stiffness in the first part of the stroke. Something else may be causing the stiffness. Did you replace the seals this time?

  • Kirtwell

Posted February 20, 2002 - 02:55 AM


h bomb,
I'm glad to hear that RaceTech got the numbers close in respect to our weights. I rode this weekend...and like you mine got softer too...I went ahead and turned the compression clickers out a few but I don't have a good jump to test it on...I will this weekend.
Could you tell me what valves they put in yours?

I honestly didn't think adding oil would stiffen up the suspension either. But it does.
Yes I changed the oil seals while I had it apart.
...Could it be so much oil that it needs revalving????
I'm not an expert either...I'm just tinkering....trying to learn a few things :)

  • MX_Tuner

Posted February 20, 2002 - 08:00 AM


It takes a few strokes for things to start moving smoothly after installing new seals. This is normal. The seals will break in some also adding to the "softening" over time.

Related Content


2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.