My current XR400 fork settings. Now what?

[Pantaz]

Here is my setup: 1997 XR400R; Rider weight = 295 lbs.; Springs = 11.0 kg/mm, 0.45 kg/mm. (Suspension was done by previous owner, but I changed springs.)

Both stacks (compression and rebound) have the same seven shims. Two .008" and five .0045" shims. Oil is Honda SS-7 (5w) at 100mm.

(Photo of shim stacks)

My main complaint is the fork action on rocky terrain. The fork feels very stiff. It's really bad going up rocky hills. I have to slow way down or the bike just pitches me off line. Is that the "high speed compression"?

I've tried the clickers on numerous combinations. I'm currently running compression at 17-18 clicks (two or three clicks from full soft).

So, the big question is, what do I change?

 

[KTM-Lew]

The first thing is stiffer fork springs. RaceTech's calculator says .527 for your weight! Too soft allows the bike to ride too far into the travel and gets very harsh. You will likely find you need to run heavy oil to help control the rebound. At least 10wt & maybe even 15wt. The stock base-valve set-up on those is junk. If you want to spend the money there are options available.

 

[Pantaz]

The first thing is stiffer fork springs. RaceTech's calculator says .527 for your weight! Too soft allows the bike to ride too far into the travel and gets very harsh. You will likely find you need to run heavy oil to help control the rebound. At least 10wt & maybe even 15wt. The stock base-valve set-up on those is junk. If you want to spend the money there are options available.

The springs I have are fine. No spacers in the forks, and the sag is right on. I went to ESP and got the springs he recommended.

The only time I've bottomed out the fork was hitting something big (never saw it) at about 40mph. Dented the rim! Works fine on small jumps, whoops, everything else.

The shims I have are not stock. From what I have been able to find, the factory setup is twelve .004" shims. The generic recommendation is remove six shims.

The stock oil is 5wt. and it's probably what I'll keep using. Heavier oil would just make things worse.

 

[KTM-Lew]

Sound like you know more about it than I do.....

 

[Pantaz]

When in doubt...

Just to update this lonely thread:

I removed the two .008" shims from the compression stack. Kept oil level at 100mm with the same type and viscosity -- SS-7 @ 5wt.

As a starting point, I set both clickers at factory recommendations: Rebound = 12 clicks; Comp = 14 clicks.

Went to Dove Canyon on Sunday. Wow! What a difference! Sharp-edged bumps and rocks that made me death-grip the handlebars... no more! It needs just a touch of fine tuning, but I was too happy to stop and mess with it.

Of course, now I notice how stiff the back end feels...