Stock KYB shocks rebuilt

FYI - Current list price on the OEM Kayaba (KYB) shocks is $427 so when it comes time for replacement, most VX owners are opting for aftermarket shocks. If you want to stay with the OEM shocks for a more reasonable price, my suspension guy can rebuild your tired and/or leaking stock shocks for $125 each - as long as you haven't run them dry too long and trashed the internals or the chrome on the shaft. He will completely disassemble, clean, install new seals and fluid and charge with nitrogen.

He can also re-valve them if you want firmer/softer compression damping and/or slower/faster rebound damping.

His website with contact info is http://www.brucessuspension.com/

(special thanks to Skidplate for donating his worn out shocks to experiment with)

This is tremendous news if its true. Has the reason for failure on our shocks been determined? can anything be done to improve prevent our failure mode?

John C.

Thats great! I know Amsoil sells shock fluid. Will someone ask him if that stuff is any good? I might take this avenue down the road.

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Originally posted by Hotsauce
Has the reason for failure on our shocks been determined? can anything be done to improve prevent our failure mode?

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Hmm, good question. Surely his knowledge and ability to rebuild can give us an idea as to why/how they may fail, and possible if rebuilding and replacing with any different components may actually make it stronger than before?

I have 2 failed rear schocks if he needs some more for testing.

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Originally posted by Hotsauce
.... Has the reason for failure on our shocks been determined? can anything be done to improve prevent our failure mode?

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I only left one shock with Bruce so he could only provide insight on why that one shock failed. (I'll have him look at the others when I pick my forks up) He thinks dirt probably killed it. All it takes is a few grains getting past the wiper and lodging between the seal and shaft and you have a leak. This particular shock had about a tablespoon of sand crammed in the area under the Schrader valve cover. No idea how it got in there but I saw it with my own eyes. That had nothing to do with leakage but the point is dirt gets into everything.

These shocks are under high pressure so once they start to leak they're going to leak fast so you need to keep an eye on them. Isuzu opted to make handling/performace a priority which resulted in a shock configuration that is more likely to leak. They reduced unsprung weight by mounting the lighter shaft to the control arm and the heavier shock body to the frame - which places the seal at the bottom of the shock. So when it starts to leak, the drain, so to speak, is at the bottom and it will leak until dry - unlike other shocks (with seal at top) that will leak profusely only until the floating piston that separates oil from nitrogen bottoms out. (Or was it tops out?)

Speaking of floating pistons he said this is the first Japanese reservoir shock he's seen that uses a floating piston rather than a bladder. It's designed like a European shock (e.g., Ohlins, White Power, Marzocchi) and is a little more expensive to rebuild because the piston is a PITA to work with. On Skidplate's shock, some fluid had actually leaked past the piston and gotten into nitrogen territory for some reason.

Can anything be done to prevent premature failure? Yes and no. He said if you guys will clean these things every now and then they might last longer. After a day in the dirt, just loosen the band clamps, drop the boot and blow the grit out with compressed air. Be careful not to force dirt into the seal though - keep the airflow perpendcular to the shaft. On the other hand, this is a high performance type shock - with 200 psi charge, mounted upside down, with damping stiffer than Ron Jeremy. It was built to perform - not built to last. And there's not a damn thing you can do about that except properly maintain your KYB or replace it with a conventional, less performance oriented (and cheaper!) shock. And by maintain he meant have them rebuilt before they leak dry and trash themselves. You guys with bikes know what it's all about right?

Thanks for all the technical information. I had tried to submit a letter to KYB in Japan to ask about the possibility of their people to rebuild, or at least some technical data, but never heard anything back.

I sent this guy an email about rebuilding, and havent heard a thing back!

They were NOT @ SEMA either yet all the other shock manufactures were - I've got a few I'd like to have rebuilt if it is ever possible.

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Originally posted by VR4-Quest
I sent this guy an email about rebuilding, and havent heard a thing back!

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I talked to Bruce the other day and he said he's changing "web guys" (I don't know if he meant ISP or web host - and he probably doesn't know either) so your email might have gotten lost in the shuffle. I doubt it though. Most likely he just hasn't checked it. He's one of the most computer illiterate people on earth. I think he's got an 8088 that pulls double duty as a door stop - but he knows shocks!

Just give him a call at 704-637-3675.

PS - I'm just kidding about the 8088. I'm sure he's up to a 486 by now...



;)