Xr400 Fork Spring Mods

[killeronadkx]

I just put in some XR400 fork springs and used a preload spacer 1.5" long. I put fork oil in 110 from the top of fork.... I am not a suspension wizzard by any stretch..... Am I in the ball park? My stock forks were really soft.... I weight about 195 in street clothes.... If anyone knows about the amount of oil could you please help me out on this? I just put on my Gnarly Desert pipe and Turbin Core II, and I can hardly wait to go try it out this weekend....I went riding this past Sunday and my Bro and friend on big 4 Strokes handed me my butt on a platter.... I got beat up bad.... I am going back this weekend SCREAMING FOR VENGENCE!!!!!
Thanks,
Randy
KDX 220 "04"

 

[jaguar]

I would preload the springs so that the sag of the suspension in the front is about the same as the sag of the suspension in the rear (when u are sitting on the bike).
If the forks bottom out on big jump landings then add more oil. (say 10mm higher)
If you are doing motocross then you should be using 15 wt oil, otherwise use 10 wt oil in the forks.

 

[John Harris]

I suspect that you are just about right to start. Try it out this weekend and see what you want to change for your riding terrain and ability.

 

[killeronadkx]

I would preload the springs so that the sag of the suspension in the front is about the same as the sag of the suspension in the rear (when u are sitting on the bike).
If the forks bottom out on big jump landings then add more oil. (say 10mm higher)
If you are doing motocross then you should be using 15 wt oil, otherwise use 10 wt oil in the forks.

The front end feels like it has the same sag as the rear.... It feels so much better than stock.... I have not rode it, but will do so this Sunday.... No moto-x for me, but I do some serious off road with nasty bumps and ruts with rocks..... I might bring some fork oil with me and do some adding up in the hills....
Thanks,
Randy

 

[canyncarvr]

If your springs are 532mm long, a 1.5" spacer would put you probably OVER 35mm preload.

Unlikely that's correct by anyone's measure.

If you used the .40 springs you will be on the low side of 'correct' @195. Using a too-long spacer to make up for too-weak springs isn't a good combo.

Set your sag on the shock.

115mm(**edit**: this is a fork oil level referencing the above..NOT a shock sag setting) is fine. Yes, more will stiffen it up.

...so will adding some clicks.

 

[killeronadkx]

If your springs are 532mm long, a 1.5" spacer would put you probably OVER 35mm preload.

Unlikely that's correct by anyone's measure.

If you used the .40 springs you will be on the low side of 'correct' @195. Using a too-long spacer to make up for too-weak springs isn't a good combo.

Set your sag on the shock.

115mm is fine. Yes, more will stiffen it up.

...so will adding some clicks.

I am going riding tomorrow up in the hills and I will do some testing and adjust the clickers. I will probably re-cut my preload spacers as per your instructions in a previous post, which was excellent by the way.... Thanks alot bro!!!!
Randy

 

[canyncarvr]

Do keep in mind that suspension settings are specific to you the rider of a particular bike. There are too many variables to allow someone to setup your bike thru an email or some other long-distance venue. Get familiar with the basics of the matter....what happens with too much/not enough compression, rebound etc. etc. and you will be able to tune your bike to suit you.

Some things are just a given. 'Fer instance...worrying about any fork clicker settings, oil levels, preload and so on if your shock sag is 5.5" is a waste of time. You may well end up kind of 'balanced', but that would only mean both ends would be wrong.