Suspension questions

5 replies to this topic
  • jasonmcc

Posted July 08, 2000 - 02:05 AM



I own a australian model 1999 wr400 and have a few questions of suspension changes. I ride a lot of motocross with big jumps. I have increased the fork oil height up to around 90mm to stop the forks bottoming hard. I like how my suspension feels on jump landings but and small bump and holes it feels really stiff. I weigh 72kg with no riding gear so I am pretty light. What should I do to make it feel plusher on small stuff. What fork/shock spring rates do you reccomend. Gold valves ?



  • Kevin_in_New_Hampshire

Posted July 08, 2000 - 02:20 AM


The bike mag trick for your situation is to go with heavier springs, (possibly) a lower oil level height and (possibly) lighter on the damping setting. This setup will give your more plushness off the top and the heavier spring rate will prevent/reduce your bottoming vice your higher oil level to prevent bottoming with your present setup.
You can try There you will find a question answer program that will recommend spring rates. You may also want to check out the spring rates for the YZF. Those standard spring rates may be more to your liking. Read some magazine back issues YZF tests to see if the mag guys recommend anything. Off of the top of my head, I couldn't tell you anything, but I too need to check it out.
Hope this helps at least a little, Jason.


99 WR, all YZ mods, de-octopused, OEM YZ tank and IMS seat, jetting by Clark, got forked by Pro Action.

For clarification: WE'LL be having a KICK ASS time in Moab!! Right Mitch?!!

  • Dougie

Posted July 08, 2000 - 02:30 AM


The WR forks come set for about a 175 lb person. Which means they are a little stiff for a lighter person. If I've done my math right, you weigh about 158 lbs.

I weigh about 160 and got my suspension done by Race Tech. Gold Valves and new fork spring rates. With the GVs, just a couple of clicks makes a difference. I get a great setup on the track and on the trails now.

Race Tech set me up with a .43 spring rate in the forks and kept the 5.0 stock spring in the rear.

As for the stiffness on the smaller bumbs and holes, that may help. You may also try softening up your rebound a couple of clicks. After my suspension was done, I took it to a track. Same problem as you, great on jumps, felt like the front wheel was coming off on washboards. The dealer said to soften the rebound and wa-laa.

Trial and error until you get a happy medium.

Dougie, '99 WR400
Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

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  • jasonmcc

Posted July 08, 2000 - 05:27 PM


I am a little confused now. Kevin reccomends heavier springs and Dougie reccomends maybe lighter springs. Both explanations I can understand but which way do I go.

  • Kevin_in_New_Hampshire

Posted July 08, 2000 - 09:35 PM


The stock fork springs are .46 for the U.S., euro is .42. Does that mean Australia is also .42?

Initially, if I bottom, I go stiffer on compression damping. If the bottoming is cured, but now it's too stiff off the top, you'll need to add oil to prevent excess bottoming. With the higher oil, you may be able to back off your compression damping a few clicks. Go in increments of two on your clickers. If is plush off the top and you are bottoming again, increase your compression clickers or raise oil height. If you are maxed on the oil level height AND your compression clickers are high/forks too stiff, you'll need to go with stiffer springs.
With the stiffer springs installed, use the minimum oil height (it is much easier to add oil than to suck it out). Set the compression adjusters to where it feels plush off the top and go do some laps. If you are lightly bottoming once or twice a lap, YOU ARE ALL SET!! If you are pushing through the fork stroke too easily or bottoming, you'll have to increase your compression clickers. Again, go two at a time. If you stop bottoming, but it has become too stiff (AGAIN!), you'll have to add oil. I wish I had a nice number to give you on oil adds, but I don't. I would guess maybe 5mm increase in oil height, volume ???. Back off the compression adjusters to gain some plushness and off to the track again. Often times you'll have to compromise on where you want your forks to operate. MX settings, in my opinion, are easier to set up. Off road settings are a different matter. You want it plush and hope you don't find any large jumps or G-Outs where you'll encounter bottoming.
Although this procedure may sound time consuming and tedious, the only tough part is the oil height.
Although I do not know if you can do it, you may be able to remove the schraeder valve (air valve) at the top of your forks to add the oil. You could add in 5cc increments. Hopefully someone who knows this may put their two cents in on it.


99 WR, all YZ mods, de-octopused, OEM YZ tank and IMS seat, jetting by Clark, got forked by Pro Action.

For clarification: WE'LL be having a KICK ASS time in Moab!! Right Mitch?!!

[This message has been edited by Kevin in New Hampshire (edited 07-09-2000).]

  • Taffy

Posted July 09, 2000 - 12:35 PM



perhaps the reason everyone is confusing you over the spring rates is because the spring you need is relevant to the type of riding you're doing. the books may say that X is the right spring for your enduro bike, but for motocross it would go up. if you're doing motocross all the time then it's the spring rates for that application you need.

if your "too light" for your spring in enduro, it's probably the correct one for motocross.


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