Rear shock rebuild

Discussion specific to the 1995 - 2006 KDX200 (H Series) and 1995 - 2005 KDX220R (A Series) models sold in the USA
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Ewbarger
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Rear shock rebuild

Post by Ewbarger »

So, I am going to rebuild my shock with nee seals and replace the bumper. Has anyone lowered the rear by internal means? I found a spacer from Zeta for a 2000 kx250. Just wondering if it would fit.
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KDXGarage
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Re: Rear shock rebuild

Post by KDXGarage »

I assume such a product would not work, as it is for a 46 mm body, not the 44 mm of the KDX.

Look at racetech.com to see if their spacers would be suitable for you. They do it differently.

Shop for a new seal head assembly, not just the seals. Just in case you were thinking of rebuilding the stock seal head. The stock steel head is peened over and a nightmare to rebuild.
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Ewbarger
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Re: Rear shock rebuild

Post by Ewbarger »

KDXGarage wrote: 12:40 pm Apr 12 2023 I assume such a product would not work, as it is for a 46 mm body, not the 44 mm of the KDX.

Look at racetech.com to see if their spacers would be suitable for you. They do it differently.

Shop for a new seal head assembly, not just the seals. Just in case you were thinking of rebuilding the stock seal head. The stock steel head is peened over and a nightmare to rebuild.
Thank you for the info. I was looking at just seals but now I will just buy aftermarket seal head. As for lowering the rear shock, it's not too big of a deal for me to ride it in stock height. It would make it easier on me on the tight mountain trails but I dont ride there very often. Steep hills and really rocky areas give me a little challenge but most of my riding is on the east coast trails.
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billie_morini
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Re: Rear shock rebuild

Post by billie_morini »

Ewbarger, I lowered (shortened) rear & front suspension by 50 mm (2 inches). Modifications are internal and reversible. Got my parts, spacers & springs for my weight, from RaceTech. They also tell you good starting points for pre-load. 50 mm is about as far as you can go. It's necessary to shorten front & rear to keep OEM frame geometry. The result is perfect. Lower seat and lower center of gravity, plus correct spring rates makes it so much more fun to ride my KDX.
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billie_morini
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Re: Rear shock rebuild

Post by billie_morini »

Ewbarger, I can't see how that Zeta ring can be used. Here are BEFORE (OEM) & AFTER (shims inserted) photos of rear shock. FYI, the shim stack is not 50 mm thick. It's 16 mm (0.6 inch). The swing arm & linkages provide relationships that factor with shim stck thickness to achieve desired lowering.
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Re: Rear shock rebuild

Post by billie_morini »

Here are BEFORE (OEM) & AFTER (spacer inserted) photos of one front fork. The spacer is a sleeve. Spacer length is 38 mm (1.5 inch) because I kept the 12 mm (0.5 inch) OEM spacer. Installing spacers in front forks and shims in rear shock is easy.
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billie_morini
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Re: Rear shock rebuild

Post by billie_morini »

Ewbarger, a few more notes.

- It's good advice from KDXGarage to buy a ready-to-use seal head assembly instead of individual parts for self-assembly. I've done it both ways. Pricing is comparable.
- Most wrenchers find it difficult to replace the piston band (ring). It's easy to tear them up when installing them without a little finesse and a lot of hydraulic oil. Here's a short page where this is discussed a little bit: viewtopic.php?f=102&t=23207
- KDXGarage mentions the stock (steel) piston rod in the rear shock is peened (and a nightmare to rebuild). If you look closely at my 1st photo above, then you can see a flat surface above the black nut. This is the peened end mentioned by KDXGarage. Also, you can see it's treatment in the images provided immediately below. It's not often that KDXGarage and I disagree on things KDX. I'll offer a counterpoint by reiterating it's easy to re-build and/or shorten KDX suspensions. Don't forget to finish-off the bevel with a wire wheel.
- RaceTech provides a very nice set of instructions for HOW TO shorten rear shocks: https://racetech.com/page/title/IP%20SP ... g%20Spacer
- A Youtube video series by MrDuhFactor thoroughly explains how to shorten dirt bike suspensions. Look for "How to Lower a dirt bike -THE LOW RIDE KRONICALS- PT 1" and subsequent parts. Most useful instructions provided for filling and bleeding rear shock
- Another source providing simple, yet thorough, instructional videos for shock rebuilding & filling / bleeding is Rocky Mountain ATV. Mechanic Charles goes slow and provides useful info & tips
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Ewbarger
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Re: Rear shock rebuild

Post by Ewbarger »

Well, I'm holding off on doing the rear shock. May send it to race tech. I'm currently working on the forks. New seals and stock springs.
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Re: Rear shock rebuild

Post by Ewbarger »

Finished the forks jut to find that the steering stem bearings are bad. So ordinary the bearings! This poor bike was neglected everywhere but the engine. The engine was gone through right before I bought it.
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Re: Rear shock rebuild

Post by Ewbarger »

I looked up oem bearings, but the parts diagram isn't showing the dust seals. Does anyone know if they come with the bearings?
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Re: Rear shock rebuild

Post by KDXGarage »

billie, where did we disagree? Just in case, I was saying to rebuild the seal head assembly would be a nightmare. The peened over end of the seal head where the top out bumper is, is the nightmare. One has to enlarge that / open it up to remove the top out bumper, washer, oil seal, dust seal and bushing. The later KX versions have an easy aluminum seal head assembly.

Ewbarger, the rubber seal is part of the OEM bearing. Aftermarket bearings may come with a sort of cap / seal / cover.
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Ewbarger
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Re: Rear shock rebuild

Post by Ewbarger »

KDXGarage wrote: 02:42 pm Apr 17 2023 billie, where did we disagree? Just in case, I was saying to rebuild the seal head assembly would be a nightmare. The peened over end of the seal head where the top out bumper is, is the nightmare. One has to enlarge that / open it up to remove the top out bumper, washer, oil seal, dust seal and bushing. The later KX versions have an easy aluminum seal head assembly.

Ewbarger, the rubber seal is part of the OEM bearing. Aftermarket bearings may come with a sort of cap / seal / cover.
Thanks for the input.
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Re: Rear shock rebuild

Post by kdxdazz »

Ewbarger wrote: 10:27 am Apr 17 2023 I looked up oem bearings, but the parts diagram isn't showing the dust seals. Does anyone know if they come with the bearings?
I just did a steering head rebuild 2 weeks ago with OEM bearings, they have built in seals . Klx250 are identical
1999 KDX220SR (KDX220-B5)
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billie_morini
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Re: Rear shock rebuild

Post by billie_morini »

Hi KDXGarage, my mistake. You wrote, "The stock steel head is peened over and a nightmare to rebuild." My misinterpretation was "peened shock rod."
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Re: Rear shock rebuild

Post by KDXGarage »

Cool. No problem.
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