2001 KTM 125SX suspension?

Sheriff245
Edited Date/Time 10/3/2019 8:42am
I’ve been looking for a mid 90’s 125 for a project but can’t find what I’m looking for locally. Stumbled upon an 01 125SX with low hours from a friend of mine.

I rode the actual bike back in the day and remember it being a rocket, but I seem to remember the suspension was pretty bad even in its time. Are there trucks to make it work decent? Or swaps that are relatively simple to do on that bike?

Any other comments, tips or warnings regarding this bike?
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murph783
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murph783 10/18/2018 3:59pm
10/18/2018 3:59pm
So I never rode one, but this would be my thought based on what I’ve heard. If you could swap a swingarm and shock in from a bike that had a linkage it would probably handle much better, but kill the horsepower advantage given by the straight intake shot that pds set up allowed.
karlz
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karlz 10/18/2018 4:28pm
10/18/2018 4:28pm
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper piston and valving on the damper shaft and use a progressive spring if its not the original/and/or for your weight.
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Sheriff245 10/18/2018 6:45pm
10/18/2018 6:45pm
karlz wrote:
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper...
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper piston and valving on the damper shaft and use a progressive spring if its not the original/and/or for your weight.
Thanks for the info. How did you get the shock to perform compared to the Japanese offerings of the same era? And what about the forks?
JMX82
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JMX82 10/18/2018 9:26pm
10/18/2018 9:26pm Edited Date/Time 10/18/2018 9:27pm
You can use later model KTM twin chamber forks on that bike that are pretty good. Good suspension tuner can make that PDS shock work really good too.

There was also SXS kit forks and shock (WP equivalent for KYB A-kit) available for KTM's back in the day but they are pretty hard to find these days.







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AJ565
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AJ565 10/19/2018 5:29am
10/19/2018 5:29am
I had a 2001 125sx. Yes that bike was a rocket and easily the most fun 125 I've ever owned. Don't get to caught up in what you read about the suspension not being very good, its not as bad as people make it out to be.
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Sheriff245 10/20/2018 4:18am
10/20/2018 4:18am
The suspension thing (especially the fork) is actually from my own memory as I rode the bike a few times back in the day. It wasn’t set up for me though.

Would the cc forks be bolt on on that bike or other parts would be needed?
MX915
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MX915 10/20/2018 6:35am
10/20/2018 6:35am
What year did they change from 43 to 48 mm forks? I know my 03 450 were 48, but I seem to recall the change was made somewhere within the 00,01,02 model years.

Not sure if the outer diameter of the tubes are the same.
JMX82
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JMX82 10/21/2018 6:19am
10/21/2018 6:19am
I did some research and I came to conclusion that in 2002 KTM changed from 43 mm forks to 48 mm forks. I think you would need to change complete front end from a newer bike to make 48 mm forks work in a 2001 model.
Moto Obsessed 10/3/2019 6:25am
10/3/2019 6:25am
karlz wrote:
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper...
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper piston and valving on the damper shaft and use a progressive spring if its not the original/and/or for your weight.
Karlz, did you have any familiarity with the SXS shock from that time period?? I have a '99 SX125, and have access to a SXS shock from a 2002 KTM 125... I'm fairly certain the 2002 shock will work on my '99, but would appreciate any input you have. Also, when you describe your modification (removing upper piston/valving on damper shaft) - I assume you mean remove it completely, and replace the main shock spring with a progressive rate spring (for my weight)... I'm trying to understand the concept behind this mod (I believe you 100% if you say it works) - as wasn't the main issue with these shocks a rebound issue, due to the shock packing over stretches of rough terrain (like whoops, etc) I am by no means a suspension tuner, just know enough to be dangerous / perform my own basic shock service - so I really appreciate any fundamental education you can share. Cheers and thanks in advance
OtotheB178
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OtotheB178 10/3/2019 8:42am
10/3/2019 8:42am
karlz wrote:
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper...
I modified hundreds of these shocks back in the day. Im not going to give detail for a individual rider/weight /terrain etc, but remove the upper piston and valving on the damper shaft and use a progressive spring if its not the original/and/or for your weight.
Moto Obsessed wrote:
Karlz, did you have any familiarity with the SXS shock from that time period?? I have a '99 SX125, and have access to a SXS shock...
Karlz, did you have any familiarity with the SXS shock from that time period?? I have a '99 SX125, and have access to a SXS shock from a 2002 KTM 125... I'm fairly certain the 2002 shock will work on my '99, but would appreciate any input you have. Also, when you describe your modification (removing upper piston/valving on damper shaft) - I assume you mean remove it completely, and replace the main shock spring with a progressive rate spring (for my weight)... I'm trying to understand the concept behind this mod (I believe you 100% if you say it works) - as wasn't the main issue with these shocks a rebound issue, due to the shock packing over stretches of rough terrain (like whoops, etc) I am by no means a suspension tuner, just know enough to be dangerous / perform my own basic shock service - so I really appreciate any fundamental education you can share. Cheers and thanks in advance
I thought that due to the PDS design they had a needle design in the shock for progressive damping however it used to seat too early cause a spike and harsh spot. Race tech did a two stage Needle which would allow a much better damping curve (the lower part would collapse into the larger top part)....but that was 18 years ago now and i'm pretty sure i've not got the full story.

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