shock hurts, but why?

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ohgood
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shock hurts, but why?

Post by ohgood »

1997 kdx220, suspension up front works well enough, but the rear is killing my back.

ive set race sag to 4", and let the clickers out all the way out both compression and rebound.

rebound is very slow, or non existent, depending on clickers.

compression varies from rock hard to squishy.

my drz is a plush Cadillac of sweet suspension goodness, in comparison.

where should I start with the shock?
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Re: shock hurts, but why?

Post by ICRage42 »

are you sure that forks aren't set too high? just a thought like making you lean back even tho your sag is correct it wont matter really.

also wrong springs too. Found that out after getting correct springs afterwards.

Follow the suspension guide too. VERY helpful. It will get you to a good starting point!

Possibly nitro recharge too. Ever rebuilt?
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Re: shock hurts, but why?

Post by JasonK94Z »

ICRage42 wrote:are you sure that forks aren't set too high? just a thought like making you lean back even tho your sag is correct it wont matter really.

also wrong springs too. Found that out after getting correct springs afterwards.

Follow the suspension guide too. VERY helpful. It will get you to a good starting point!

Possibly nitro recharge too. Ever rebuilt?
So what is and how do you measure front fork height? Would this be sag also?
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shock hurts, but why?

Post by adam728 »

Start with greasing all the linkage and swingarm bearings. I've seen that issue numerous times on all makes and models of bikes. Will kill any chance of making the shock work right.
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Re: shock hurts, but why?

Post by ohgood »

ICRage42 wrote:
1are you sure that forks aren't set too high? just a thought like making you lean back even tho your sag is correct it wont matter really.

2also wrong springs too. Found that out after getting correct springs afterwards.

3Follow the suspension guide too. VERY helpful. It will get you to a good starting point!

4 Possibly nitro recharge too. Ever rebuilt?

1 i don't think the fork height is going to effect the rear's actions much, at my weight (225lbs).

2 i can only assume the springs are stock, i have no baseline other than assumptions so far.

3 i've seen a few guides, they normally start with 'set the clickers to x,y,z and the sag to q" which is what i've done so far. there is very little difference other than complete lack of motion from the assembly when going from the least to more compression/rebound of the shock. (this likely tells one of you exactly what the problem is, but i'm not a suspension guru)

4 nitro recharge hasn't (nor rebuild) been done by me, and i have no history of the last rebuild.
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shock hurts, but why?

Post by ohgood »

adam728 wrote:Start with greasing all the linkage and swingarm bearings. I've seen that issue numerous times on all makes and models of bikes. Will kill any chance of making the shock work right.


i've done that recently when i replaced the drop links with stock links. i don't think the pivots/bearings are the issue right now, as the shock does move freely but:


a1) full compression settings = no movement of the shock on compression after an inch or so
a2) full release of compression settings = squishy soft rear end


b1) full rebound settings = very slow rebound, as in, go make lunch, eat it, drink 2.3 beers, THEN see if it's returned fully. yes, i'm being serious.
b2) full rebound settings released = basically it's a pogo stick back there


my spring preload is set to about 3.7-4" race sag (me sitting on the bike) which from my understanding is correct. i really think it's the lack of PROPER movement of the shock on both compression and rebound, but don't know suspension well enough to determine what it needs from the A's and B's I listed.

once again, you guys know this stuff much better than me.

if it would be easier to just toss the stock shock, or pay someone to 'rebuild' it for $50, i'm ok with that. point me a direction and i'll take it.

thanks !
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Re: shock hurts, but why?

Post by KarlP »

Getting a shock rebuilt is like pulling on a new pair of sneakers. I think I'd start there, and verify that your spring is the right weight.

Your A's and B's make it seem like you are getting responce from the clickers. I'm sure you've tried putting the clickers in the middle of the range.....

I have a thought in the back of my mind that very slow rebound is caused by a low nitrogen charge. Someone else will chime in.
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Re: shock hurts, but why?

Post by Postigo »

If your rear sag is 4 inches with the stock spring at your weight then the rear spring is almost fully compressed and that's why you are getting beat up by your rear suspension, you need a new spring for your weight and is not a bad idea to service the shock at the same time.
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Re: shock hurts, but why?

Post by bufftester »

The first thing you have to do is spring it for your weight. Being a bigger guy like me you are going to have little comfort with the stock shock regardless of clicker settings. Stock the KDX is unbalanced (front is good for a 140lb rider and back good for a 180 lb rider....neither any good for a 225lb rider). Get the right springs first, then rebuild them when you change the springs (easy job) and your back will thank you
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shock hurts, but why?

Post by ohgood »

well, i found out why it was killing me-

the "oil" was more like used, burned, cooked, and then vomited from a yack than it was oil, and there was no charge on the bladder. going to filler up with fresh oil and nitrogen and see if it helps. i don't need enough spring for jumping 40' doubles, but i'd like it to not kill me. if this isn't any good i'll look into some drz replacements.
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Re: shock hurts, but why?

Post by SS109 »

Postigo wrote:If your rear sag is 4 inches with the stock spring at your weight then the rear spring is almost fully compressed and that's why you are getting beat up by your rear suspension, you need a new spring for your weight and is not a bad idea to service the shock at the same time.
Actually, 4" inches (101.6mm) of race sag might be spot on. Kawasaki recommends right around 100mm plus or minus 5mm.

Ohgood, yeah, to keep your shock working at it's peak the shock should have the oil replaced every season. Your seals will last longer and your back will thank you. Of course, having the proper spring for your weight will help as well!
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Re: shock hurts, but why?

Post by Postigo »

Having 4 inches of sag with 225 pounds on the factory spring is impossible unless you get almost all the adjust out of the shock spring and that will cause limited travel in the rear shock. In other words your rear suspension will beat you really bad.
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Re: shock hurts, but why?

Post by SS109 »

Postigo wrote:Having 4 inches of sag with 225 pounds on the factory spring is impossible unless you get almost all the adjust out of the shock spring and that will cause limited travel in the rear shock. In other words your rear suspension will beat you really bad.
Yes, if he has the stock spring. Who knows what spring he has? He needs to have it tested to see what it is.
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shock hurts, but why?

Post by ohgood »

well, that went poorly. spent the afternoon tearing apart the shock, refilled with ATF (since some said it's the beez kneez), had it recharged with 160psi nitrogen, reinstalled, and POOF

nothing. nada. zero difference at all.

i bounced on it a few times in anticipation of buttery-smooth swingarmage, and was very surprised that nothing had changed at all. went around the block with zero proload (besides the collars just tightened on the spring) and the clickers backed off 15, for compression and rebound.

i didn't even get up the driveway before saying "terrible, completely terrible' to myself.


so, i'm done with the stock shock, it is ****, or the current combination of spring + stock = **** anyway, and i'm not planning on spending $$$$$ to figure out what the current spring is, or why the current settings suck this bad....



what's a good replacement shock ? kx ? drz ? i'm looking for 'old guy plush', not 'wannabe racer wood'.

i'd like to ebay one this evening and rebuild (yay, NOT) it this weekend if possible, so NEXT weekend I can ride, maybe. :)

thanks !
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shock hurts, but why?

Post by SS109 »

The stock rear KDX shock is a great shock and is normally very plush. You really won't gain anything over trying to swap in another shock. Take it to a suspension guy, have it gone through, have your spring checked for rating and replace if necessary, and you'll be good to go. Besides, you will have to at least do some of the very same things to any shock you buy to replace it.

Just an FYI, I had the same problem with my KDX. Rear end was kicking me in the ass hard every ride. Took it to my local guy and he had to replace one seal and change the oil out. After that my shock was back to being the comfy shocked it used to be. If you can't find anyone local that will do it at a good price, check out Donnie at ZR1 Suspension in Tucson, AZ. Nobody beats his prices and the guy just does good work. He does all my suspension work and a lot of the guys from my club as well.
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shock hurts, but why?

Post by ohgood »

i'm going to save this information and pick one to rework my shock if/when i find a similar one to substitute it for the downtime.



good news is, this past weekend i rode the shock, and it didn't suck. made me scratch my head, because just up/down the driveway it was terrible, but after a little single track it loosened up some. still not wuat I would call 'plush' or 'nice' but much more agreeable with my spinal column.

I haven't seen a grey spring before, most of the others i see are purple. i wonder if this is sprung for a much heavier rider, or from another bike / shock al together. hmm


anyway, this is back burnered until i can find a suitable shock to stand in, and a front end to swap. after riding two ktm 200's, a ktm 250, i'm really wanting to upgrade the suspension. the kx500 was NOT going to be touched by me. no sir.
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shock hurts, but why?

Post by SS109 »

RaceTech's springs are grey. I have one on my shock.
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Re: shock hurts, but why?

Post by KDXGarage »

Rebuild it, not just change the oil.

Race Tech springs have been blue for several years (eight?). They were grey SEVERAL years ago.
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Re: shock hurts, but why?

Post by ohgood »

Jason wrote:Rebuild it, not just change the oil.

Race Tech springs have been blue for several years (eight?). They were grey SEVERAL years ago.

i understand, but the spring is supportive, not damping. as soon as I find a stand in, it will get shipped off, but more likely I'll find a kx500 front end first
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Re: shock hurts, but why?

Post by SS109 »

ohgood wrote:
Jason wrote:Rebuild it, not just change the oil.

Race Tech springs have been blue for several years (eight?). They were grey SEVERAL years ago.

i understand, but the spring is supportive, not damping. as soon as I find a stand in, it will get shipped off, but more likely I'll find a kx500 front end first
There are some on Ebay right now as low as $50.
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