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XR 400 Suspension Help

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1998 XR400 ,I have had the stock suspension since 1998 and never really had a problem with it, I recently decided to race it, East Tennessee trails, and everyone said I needed to update the suspension. I had a local proffesional suspension shop set it up with race tech .46 in front and a 8.5 spring in the rear. We set up the sag and clickers 95mm on race sag, 40 static. I could not make a turn and the thing beat me to death. This suspension expert is used to newer bikes not xr's, Stock it came with a very stiff rear and soft front, was this on purpose to offset something? The rebound on the rear is very very slow at the fastest setting. Any advice greatly appreciated. I weigh 160.

Edited by tennxr400

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At 160 with .46 front springs, your rebound will be way to fast even set at max. (3 clicks from full hard is stock setting). That's assuming a spring change was all that was done. With too fast front rebound, your front end won't settle into the turn, it will rebound to quick (mid turn) and make the handling weird and un predictable. Your weight is close to mine,, try .43 kg fronts (max), use oil height to dial in bottoming resistance, and a 8.5 kg or 9.0 kg rear spring. I've had better luck with 100 - 105mm race sag in the back and about 55-60mm in front. If the front is still too harsh, consider removing some shims from the stack to decrease high speed compresion. Do a search for XR400 shim stack mod. Stock valving has a mid stroke spike that can almost feel like your bottoming in some situations. Good luck man, I'm sure others can offer better advice than me but this ^ seems to be the norm for set up.

Edit - If you don't want to buy another set of front springs, run 1 stocker and 1 .46 kg. that should get you real close to .43 kg.

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On your shock, make sure you have the function of the clicker direction right in your thinking. The rebound is the adjuster on the clevis. Turning it clockwise is slower rebound. So if it's too slow, make sure you turn it counter clockwise to speed it up.

Was anything else done to the shock beside just a spring change? Like valving, fluid change or the like?

I don't know what a 185 shock spring is. Stock is a 9.8. I too recommend a 9.0., set sag at 105mm.

It seems odd to me that you'd have as much as 40mm free sag with 95mm race sag, unless the "185" spring is even lighter than a 9.0.

I agree with Mich400 that the .46s seem too stiff for your weight. Race Tech says to use .48s and I don't agree with that either. They give a recommended range of springs, .43s being near the light end and the .48s being the heaviest of the range.

For trail riding and a little enduro stuff you want plush suspension that will soak up the rocks and bumps.

All the clickers were probably set as a guesstimate. You'll need to play with them from there to dial in the ride and handling for what you're doing.

Do you know what wt. fork oil was used?

How high in the triple clamps did he set the forks?

Check your forks compression clickers(bottom of the forks) to see how many turns out from seated(full hard) they currently are and how many clicks total you have from full in to full out. Do the same with the rebound clickers in the fork caps and get back to us with those figures.

Sorry you didn't ask here first before taking it in.

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Thanks for the reply. That is what it was doing, I could not make a turn to save my life, I will have him change the front to one stock one .46, and I we will increase sag. Agian thanks for the reply.

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Trailryder, A complete service was done on both. He is going to dissasemble the rear again to find out what was going on. All the way slow was slower all the way fast was still way to slow. 185 was a 8.5., I am thinking of the 9.0 but the sag measurments we took said the 8.5 was correct for my weight, but it came with such a stiff rear shock that it makes me think the bike was designed for a stiff rear? I used to have the shocks in the stock position acording to the manual I think it was 4 down from the top, but for the race I put them at 2 down from the top because I thought it might help with the front end tuck. I think I will put it back to stock. The compression clickers where all the way soft/out and th etop clickers where at 12 clicks.

Thanks for the reply and any future advice

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Trailryder, A complete service was done on both. He is going to dissasemble the rear again to find out what was going on. All the way slow was slower all the way fast was still way to slow.

Yeah, something isn't right with it.

185 was a 8.5., I am thinking of the 9.0 but the sag measurments we took said the 8.5 was correct for my weight, but it came with such a stiff rear shock that it makes me think the bike was designed for a stiff rear?

Ok, your sag measurements make a little more sense now. An 8.5 is pretty plush. I think current free sag is a bit much at 40mm. Are you sure you took that measurement right? Because it seems to me that the amount of preload an 8.5 spring would need for your weight, to measure 95mm of race sag, would result in a lot less than 40mm of free sag.

Is it just me? Guys?

If that 40mm is correct, Then if you set the race on it to 105mm, free is going to be even more. If you put a 9.0 spring on it and set race sag on it to 105mm, free will fall back in line closer to the recommended 25mm. Even if it remains near 40mm, 40mm free at 105mm race is better than 40mm free at 95mm race.

Another possibility that could be going on is that you have just swapped what was an unbalanced stock suspension, end for end. What was a stiff rear and a too soft front end stock, you've swapped for a too stiff front end(with those .48s) and a soft rear end.

In that scenario, with the bike under its own weight(free sag), a too stiff front end will cause the bikes weight to be shifted towards the rear, causing more sag, hence that 40mm, that to me seems odd for 95mm race on an 8.5 spring. :busted: Plus front end rake increases, making turning worse, making you need to raise the forks in the clamps to try to compensate.

I used to have the shocks in the stock position acording to the manual I think it was 4 down from the top, but for the race I put them at 2 down from the top because I thought it might help with the front end tuck.

If it was indeed front end tuck you were experiencing, lowering the forks in the clamps should have been the answer, but then again, if you have what I described above going on........?

The compression clickers where all the way soft/out and the top clickers where at 12 clicks.

At 12 clicks out on the fork rebound(going by my 2000 model), that should put rebound at or near all the way out/soft. Not good. Those .48s are going to want to return to their extended length ASAP, what with compression being full soft and allowing as much compression travel as possible for the terrain. That needs to be controlled.

With the bike setting level under its own weight, have you measured front end free sag? What about race sag for it?

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No we did not check front sag. The race was Sunday and it beat me to death, when I am not so sore I will tear it down take it over to him and he is going to re-do everything at no charge, using the info from you guys. He is certified by racetech and he went by their specs which were way off with the front. It is a shame I did this right before my first race! I will re post and let you guys know what we do and how it works.

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A needle was stuck in the rear shock causing super slow rebound, that is fixed,

we installed .42 in front.

The bike is much better now but I am still feeling a bit disconected from the front.

With the 8.5 rear and .42 front sag is as follows (without boots and helmet 8lb or so)

Static-38mm (1.5in)

Race - 88.9mm (3.5in)

I had read that 85mm sag works best on xr400 but some say 100-105.

What do these numbers look like to you suspension guru's?

Any feedback appreciated

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