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Old 04-11-2006, 08:36 PM   #1
bmwktmbill OP
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KTM Adventure-lowering the suspension internal mods

Hello everyone,
My suspension is in a pile and I am ready to tear into it to drop the seat height 2-3 inches by internally modifying the suspension.
Anyone done this? Advice? I tried lowering links but was not happy with the results.
Bill in Tomahawk, WI.
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Old 04-11-2006, 09:01 PM   #2
holycaveman
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For the shock, There is a couple of ways to do this. The easiest way is add a cushion behind the base valve. This will cause the shaft to ride further up in the shock body. I would only go no more than an inch though.
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Old 04-11-2006, 09:16 PM   #3
bmwktmbill OP
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Cave,
An inch just doesn't get it. I am 5'10 and travel with a hundred pounds of gear. I hate it when the damn machine falls on me. I gotta get both feet on the ground.
Bill in Hatchet Creek, WI
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Old 04-12-2006, 01:51 AM   #4
ErrinV
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What didn't you like about the lowering links? I've just lowered my bike just under 2 inches using the Kouba Links and am pretty happy. I also slid the forks up and put on a lower seat. Now I can comfortably put a foot down. I haven't noticed any drawbacks of having less clearance yet, but maybe I will.

I'll follow this thread to see if there's a better way to lower it.


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Old 04-12-2006, 06:37 AM   #5
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Links

I have a set of Kouba links in my tool box if you want to try them out
PM me your address and I will send them to you

I used them on my Baja trip because the bike felt scary tall with the bags. Dont use them any more tho'
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Old 04-12-2006, 07:00 AM   #6
KenR
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I just had my suspension revalved and resprung. My suspension guy was suprised to find that the Adventure already had spacers in the fork and shock to lower it, installed from the factory. He said without them, the bike would probably be 2" taller - stock!

I wonder if those spacers could simply be made longer to lower it more?
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Old 04-12-2006, 07:06 AM   #7
Arch
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Guys, even with just over an inch of lowering, if running knobbies, an LC4 Adventure will bottom hard on big hits. The suspension also works differently because you're already into where the linkage thinks bumps are. I ran the links for a while and then swapped things back after a big desert ride. 'Course, for casual dual-sport usage it won't be much of a problem, but be advised that your suspension will change, and if you're pounding offroad and/or a bigger rider, your knobs will meet your inner fender.

I'd contact Boejangles for a custom scooped out seat instead.
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Old 04-12-2006, 08:51 AM   #8
meat popsicle
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So my bike could be 2" taller?!?

Arch, it was my understanding that the WP suspension could be upgraded to suit the rider and their style practically 'without limit'. If a top shelf mountain bike suspension can be setup to absorb 60' drops (I assume or an MX suspension), then ours should be able to be resprung/revalved to accomodate much without bottoming out.

Perhaps I read your post wrong?
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Old 04-12-2006, 10:22 AM   #9
ErrinV
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Quote:
Originally Posted by Arch
I ran the links for a while and then swapped things back after a big desert ride.

I'd contact Boejangles for a custom scooped out seat instead.

So did you end up lowering your 640 differently, or is it just stock now? Besides a seat, what are the better ways to lower the bike?


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Old 09-28-2007, 08:57 PM   #10
KTMitch640
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Quote:
Originally Posted by bmwktmbill
Cave,
An inch just doesn't get it. I am 5'10 and travel with a hundred pounds of gear. I hate it when the damn machine falls on me. I gotta get both feet on the ground.
Bill in Hatchet Creek, WI

yep me too, bought a set of Kouba links and going to raise tubes a few mills, should be good to go.
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Old 04-22-2006, 09:50 PM   #11
bmwktmbill OP
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Rear shock rod length for KTM Adventure, shock bottoming?

Hello,
Can anyone out there measure the rear shock rod length for the Adventure bike. I swear I measured 2.5 inches before you get interference with the rubber bumber. Am I right? I would measure mine but it is off for mods and a rebuild. Also does the rubber bumper actually compress in use. Mine seemed almost solid.
I am trying to calculate rear wheel travel and can't get to the figure listed in the manual of 300 mm(12 inches). Also no way can I get the rear wheel to hit anything up in the fender area assuming a 13 or 14 inch radius for the rear wheel and tire. With 2.5 inches of rod travel I only get 7 1/4 inches of actual wheel travel. I know people are complaining of bottoming out, I just don't see how it can happen. Anyone been down this road? I can't make sense of it.
Thanks.
Bill in Tomahawk
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Old 04-22-2006, 11:21 PM   #12
holycaveman
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Your rear shock bumper squashes down a bit, in calculated travel. And its your linkage/swingarm etc that gives you your overall travel, not nessasarily the rod length.

Also a longer rod won't increase bottoming. The problem is the adventure is sprung like the KLR. Just for moderate offroading, in order to keep the nice ride for the street. If you want offroad bottoming resistance you need to revalve it.
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Old 04-23-2006, 10:41 AM   #13
bmwktmbill OP
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Cave,
Not sure what you are saying. I suggest you disassemble the rear suspension on A KTM Adventure, clean and grease it and get out a measuring tape and start measuring with the wheel off. There are three moving parts, the shock rod, the connecting link/pivot and the swing arm. If you lay under the machine and look up you will very well understand how it works, that it is linear on the KTM and that one controls the other so that if the shock compresses 2.5 inches the link/pivot moves the swingarm via the pivot thru an arc of 7 1/4 inches. Brother, these parts are made of steel and that is how it is. You can't change anything unless you change the length of one of the components. All are related to the other.
I sure wish someone else would try this so I could understand why the rear wheel travel is so limited when I actually measure what is going on. It would help me if someone could stick a tape on their rear shock and measure the length of the shock rod to the rubber bumper with the rear wheel off the ground. I don't need exact, just approximate would really help right now. Should be around 2.5 inches?
Thanks,
Bill in Tomahawk, WI
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Old 04-23-2006, 11:44 AM   #14
meat popsicle
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bill,

cave said "revalve", and while I don't claim to understand the mechanics of the supension, many folks who seem to have a good handle on it, and the professional shops who do this for a living, say that revalving is a component of reworking the suspension.

I am guessing that the valve(s) must be like jets in a carb, metering the shock/fork fluid. Change how fast the fluid can move from one portion of the shock/fork to another would alter the way it responds.

Perhaps this is not a linear process either. Sure would be nice to read something on how these items work; I am tired of just floating by on hope...
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Old 04-23-2006, 04:49 PM   #15
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Hell yes the valving is non-linear!!! That is the big problem with changing the links, which are also non-linear - most are quite progressive in order to provide supple motion at near full extension yet firm up through the stroke to resist bottoming. (The KTM/WP PDS system is a notable exception.) Two inter-related curves - futz with just one and you can very easily make things worse. How much of this you notice depends on what characteristics are important to you.

A simple (hopefully) explanation of your shock mechanism, for those unfamiliar with it:

Shock valving is simply a piston with holes (orifices) in it with a series of thin, flexible washes stacked over the holes. This is called the shim stack. By varying the flexibility, number and spacing of the shims, the stack can be extremely fine-tuned to react differently to the varying oil flow requirements.

The piston is fixed to the shock shaft. When the shock moves (compression or rebound) the piston must move through the oil bath contained in the shock body, so the oil must flow through the holes in the piston and push the shims out of the way. The way the shims move in relation to different loads gives you the reponse curve of the shock. There are two sets of holes in the piston and a shim stack either side; one for compression, one for rebound. Cartridge forks have two much smaller pistons, each with one shim stack.

Note also that the rebound/compression adjustment clickers cannot change the shape of the response curve of the shim stack. They are a simple needle valve arrangement for a bypass to the piston. Essentially they only raise or lower the entire curve. Changing the shape of the curve requires changing the shim stack. Typically, the rebound knob is on the bottom of the shock because the bypass is up the middle of the shock shaft; the compression adjuster is on the remote oil reservoir to alter the flow from the shock to the reservoir.

So there will be shims to allow small oil movements for small bumps. There will be shims that will rapidly open a big hole to allow oil to flood through, such as when you hit a big bump and the wheel has to move a long way fast. Plus everything in between...that's where it gets complex and you just hand it over to your suspension fellah and say, it's doing this, and I want it to do that...

An example: my '95 Triumph Trophy runs an Ohlins Daytona shock. If the rebound clicker was set soft for small bumps, it would weave on high-speed corners. Set hard to get rid of the weave, it was harsh on small bumps. My Ohlins man compared the shim stack to the '96-on Trophy, and noted that Ohlins had firmed up the low-speed (weave) damping...so he simply installed that shim stack...voila! Perfect! or pretty damn near it.

I have heaps and heaps of documentation with diagrams etc. Let me know if you want more info, I will dig it out for you. It's also bound to be online somewhere.

[Edit]
Yeah, try here: http://www.ohlins.com/mc_when_you_are_riding.shtml
Woulda saved me a lotta typing!

And see this: http://www.off-road.com/dirtbike/mar...b101shock.html
More pcitures and explanations.

Enjoy!
[/Edit]
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warewolf screwed with this post 04-23-2006 at 05:14 PM Reason: Add link to Ohlins, and again for another
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