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XR 400 Rear Suspension

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I know this has probably been beaten to death, But....... I'm 5'10"  212 lbs without gear. Running stock rear shock. Is replacing spring with a 11.5 kg spring a good way to go? I ride all trails in the North East. Rough and rocky.... Just looking to do something with rear suspension with out breaking the bank. Any suggestions? 

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11.5 is what I would recommend, but you should also consider the fork springs as well- stock is .38, for your weight you need .485

 

Having the shock serviced and recharged is worth every penny if you already have it out of the bike. 

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I am also 5' 10", about 200 without gear.  

Number one thing you need to do is set the race sag.  I set mine at around 4".  I then checked the free sag; don't remember the exact number, but it was close enough that I decided not to bother with the spring.

Here's the problem with your stock shock:  the valving in it is WAY off.  It has a ridiculous amount too much rebound damping, both high speed and low speed.  Low speed compression is about right, but it has way too much high speed compression damping.  

The only solution is to revalve it.  Contrary to what you'll hear from a lot of people, I thought disassembling and revalving the shock was easier than disassembling and doing the shim stack mod on the forks.  Pull everything apart, remove some shims, put everything back together (with new seals as a good idea), fill with oil, get a shop to charge with nitrogen (~$15 around here), and you're done.

If I think of it, I'll post up the final shim stacks I wound up with on my shock later tonight, as well as the walkthroughs I used to help me through it.

The end result was phenomenal.  It still has more than adequate bottoming resistance, tire stays stuck the ground very well, and perhaps most noticeably, it absorbs sharper/faster hits MUCH better.  It is very, very smooth over rough terrain (and trust me, here in NC, we have PLENTY of those rocks you're talking about).  In my opinion, I think it made a bigger difference than the shim-stack mod that everyone talks about for the forks, and was cheaper and easier to do.  I'd HIGHLY recommend getting it revalved.

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23 minutes ago, sneaky98gt said:

If I think of it, I'll post up the final shim stacks I wound up with on my shock later tonight, as well as the walkthroughs I used to help me through it.

 

You should definitely do that. There's very little of that kind of info around here.

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2 hours ago, Trailryder42 said:

You should definitely do that. There's very little of that kind of info around here.

Sure thing.  If for some reason you don't hear from me in the next day or two, reply again to me so I get another notification.  I stay so dang busy at work and at home these days, that I forget half the things I post online.

I definitely want to post it sometime, because I spent so much time researching it beforehand that it'd certainly be very beneficial to other members to use what I found.  I read through a ton of posts back from the late 90's to early 00's regarding what guys did back then.  I kept hearing guys talk of a spreadsheet with this valving information in it, but when I went to download it, it was either dead, or obviously not the same spreadsheet they were talking about.  Well, I did a ton of digging, and wound up finding a website that was hosted by one of the members posting.  Doing some more digging around that website's directory, I actually found the spreadsheet under a different file name, and was able to download it.

So, between that spreadsheet and recommendations from members on what they did, I made my own shim stack combo and added it to the spreadsheet.  As I mentioned, I've found that it works VERY well.  I'll do my best to remember to post everything up sometime soon.

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Thanks for the info guys.... I'll wait for extra info and start digging in. 

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On 5/23/2017 at 11:47 AM, sneaky98gt said:

Sure thing.  If for some reason you don't hear from me in the next day or two, reply again to me so I get another notification.  I stay so dang busy at work and at home these days, that I forget half the things I post online.

I definitely want to post it sometime, because I spent so much time researching it beforehand that it'd certainly be very beneficial to other members to use what I found.  I read through a ton of posts back from the late 90's to early 00's regarding what guys did back then.  I kept hearing guys talk of a spreadsheet with this valving information in it, but when I went to download it, it was either dead, or obviously not the same spreadsheet they were talking about.  Well, I did a ton of digging, and wound up finding a website that was hosted by one of the members posting.  Doing some more digging around that website's directory, I actually found the spreadsheet under a different file name, and was able to download it.

So, between that spreadsheet and recommendations from members on what they did, I made my own shim stack combo and added it to the spreadsheet.  As I mentioned, I've found that it works VERY well.  I'll do my best to remember to post everything up sometime soon.

Please post this. I am about to have to revalve a shock that was done professionally- and is so light the bike has almost no dampening.

 

The 11.5 shock spring that the first poster asked about is TOO HEAVY for a 212lb guy unless he is a pro level rider. 10.4 is more applicable. IF you don't believe me buy a sag scale, buy the Honda competition manual for the XR400R, and go through the sag setting procedures. In my experience a .50 spring will be needed for the front if running convention forks, probably around .46 if running USD forks. I am a lower A class racer/rider.

On 5/23/2017 at 3:00 PM, XRTony said:

Thanks for the info guys.... I'll wait for extra info and start digging in. 

 

Edited by Firestone

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Thanks for the info guys.... I'll wait for extra info and start digging in. Thanks for spring info. I'll go through sag set up and keep stock spring. Think I'd like to revalve it. sounds like the way to go. Just need to find some time. lol  I'll wait for that valving info. Thx again

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I am 195 before gear and my current XR4 came with an 11.5 spring, it was a buckboard. Went back to the oem and it is just right. It had been re-valved by Pro Action and the valving works pretty well.

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