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Zander Beaver

KTM 250 sxf suspension help

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Hello,

 I have a 2008 ktm 250 sxf with racetech gold valves front and rear. I originally got a valve setting for a intermediate B class rider .46 stock fork springs p10 progressively wound spring. The bike moved around too much and bottomed very hard. I contacted racetech and got a expert A class setting .46 springs. The bike still bottomed so I got a professional prefers stiff setting with .49 springs. The bike still bottomed but not harshly anymore and it had excellent traction. I than stiffen up the midvalve and now it doesn’t bottom excessively but I can only ride a couple minutes before It beats me up. I ride a shale mx track with 50ft doubles 70ft flat lands and 2ft deep sx style whoops. What can I change to help the bike not beat me up as bad? Every time i put my bike on the stand I bleed the forks and they push air out for around 6 seconds is this normal? I have the bars and levers set to my liking. Any help is appreciated. Thank you in advance. 

Modified midvalve 

(1) .15x20x8

(4) .10x20x8

.10x18x8

.10x16x8

.10x14x8

.10x12x8

.15x13x8

(2) .10x14x8

.20x14x8

.15mm float

30psi in bladder (17.5) recommended 

cartridge is bled correctly

fork settings

c 10 out

r 20 out

flush with triple clamps 

shock settings

sag 107mm

lc 13

hc 2 1/3

r 27

03BAF016-F633-4F7A-B965-B0D4B38CAAC6.thumb.png.71439058d73b65b3aa5993401f6ef579.png

 

3C1D66E7-1061-4BD0-B8FF-1F668EC6D38D.png

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Posted (edited)

Have you experimented increasing the oil volume?

(380cc listed in the RT chart)

 

1 hour ago, Zander Beaver said:

70ft flat lands

I'd think to prevent bottoming on major flat landings like this it will likely have to be stiffer than ideal everywhere else.

Edited by mlatour
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Your chart recommends lighter 5W fork oil, are you sure your forks aren't deflecting rather than bottoming?  

Have you tried the zip-tie around the tube trick to measure travel?

 

Sorry can't help you with the bladder as I'm not familiar with that.

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6 seconds of air isn't normal 

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I didn’t think so but the temperature changes about 15 degrees in a day so I thought that might be the reason. Is it common for the bladders to leak; I checked mine and they lost 10 psi. Would a leaking bladder cause 6 seconds of air when I bleed the forks? Thank you. 

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3 hours ago, Zander Beaver said:

I didn’t think so but the temperature changes about 15 degrees in a day so I thought that might be the reason. Is it common for the bladders to leak; I checked mine and they lost 10 psi. Would a leaking bladder cause 6 seconds of air when I bleed the forks? Thank you. 

They should not leak 

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First of all don’t bleed the air out of the fork until they’ve cooled down or you’ll create a vacuum when they do. Secondly, you didn’t state what you set the shock sag to or did you set it?

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17 minutes ago, jcolleymx said:

First of all don’t bleed the air out of the fork until they’ve cooled down or you’ll create a vacuum when they do. Secondly, you didn’t state what you set the shock sag to or did you set it?

Did you read the first post? sag 107mm

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No, thx. Sometimes it’s difficult to navigate this forum with my phone. So are you just having trouble in front?  It’s more pressure in the bladder that would help not less. Experiment with the compression adjustment knobs?

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Thanks for all the responses

I bleed the forks before and after Every ride  so I have a fresh start 

Sag is 107mm

i have the bike feeling very balanced and it has excellent traction 

shock setting is spot on

fork setting 

c 10 out

r 20 out

oil level is 405cc 15 wt

17 psi in bladder (I can not feel any noticeable difference with 17 psi vs 30 psi)

I switched to 15wt because it has a better feel than 5wt

when I soften up the compression the forks dive too much

with the stiffer midvalve setting I have 1 inch of fork travel left which is nice for over jumping but I would like to use all the travel. 

I only want to make the forks more plush in the first 4-6 inches of the travel. I don’t want to give up a lot of bottoming resistance. 

I like the stiffer midvalve setting. I am considering changing the compression stack by removing 1 face shim and or lowering the clamp shim by 1 mm. What is the better option? Thank you.

 

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The mid valve float is very stiff. Fork oil air gap and stiffer on low speed compression 

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The stiffer midvalve really helps keep the forks up in whoops. Mxcapps, are you suggesting lowering oil level and stiffening the compression stack? Thank you. 

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Use oil level to help bottoming oil is kind of  in compressible u can increase oil level If front end feels like a a basketball u added to much oil the Less  the float the stiffer it is but it will also make  For harshness. What happens if you add more compression say 5 turns out. If it gets stiff er at bottom and smoother Through stroke then change compression stack. 

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If you have a SHORT video of you on the jumps and woops, seeing how the bike is responding might help. 

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Have you considered going up a spring rate? That might help hold the bike up higher in the stroke where it’s less harsh and not dive on you. You might be able to soften damping after that so it’s not so harsh on you. 

Edited by JohnnyB24

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