Suspension help anybody?

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#1
After seeing all of the recent posts regarding the KTM suspension, I am set to jump in myself in hopes of upgrading.

Does anybody have any info on a good starting point? I own a 2001 520SX. My ability is vet novice and I ride mostly motocross tracks. My weight is in the area of 200 to 210lbs.

My bike is currently stock. If I go with heavier fork springs will the shock spring need adjusted as well? Any ideas on fork oil weight and height? Any help would be appreciated as I am hoping to get a "better" ride without the cost of a re-valve.
 

Shaw520

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#2
J.Mac, IMO the forks are in more need of help, I went with .50 fork springs and I think 8.5 in the rear, I havnt got a chance to try it out yet,(still waiting on few new parts before putting it back together). For your weight you'll probaly find .46-.48 will work good in the front, and 7.5- 8 in the rear. Try to set the sag around 35mm static, and 95-100mm race. I'll post my results after this weekend, theres gonna be a heat wave,(50 degrees) hehehe!
 
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#3
Thanks, looking for ward to the report.

Any thoughts on fork oil weight and volume compared to stock?
 

Shaw520

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#4
Personaly, Once you have enough preload w/proper sag, I feel that the lighter wt oil will work better 2.5-5wt at 120-125mm from top. No need to make them any more harsh w/10wt.

[This message has been edited by Shaw520 (edited 04-03-2001).]
 

Shaw520

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#6
HIG4,That is a good informative page, but keep in mind that the air chamber only produces resistance at the last 30% percent of the stroke, to bottoming. If your blowing through the first 2/3rds of the stroke, you need higher rate springs to utilize the full stroke. IMO, anyone over 160 pnds riding aggresively, will want stiffer springs to keep the bike at a proper stance, 95-100mm race sag. Compression dampning and rebound dampning are another ball of wax.
 

jeb

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#7
Originally posted by JohnnyMac:
Does anybody have any info on a good starting point? I own a 2001 520SX. My ability is vet novice and I ride mostly motocross tracks. My weight is in the area of 200 to 210lbs.

My bike is currently stock. If I go with heavier fork springs will the shock spring need adjusted as well? Any ideas on fork oil weight and height? Any help would be appreciated as I am hoping to get a "better" ride without the cost of a re-valve.
What kind of riding are you going to do with this bike? Different setup for woods than it would be for MX/SX.

The SX should have come with a PDS3 (or maybe a 7?) so that should be about right for you in the woods. I'm sure the fork springs are stiffer, too, but I have no idea how much so. I just ordered .46's for my 01 400E forks. Stock is .42 for the MXC/EXC. I weigh the same as you and only ride in the woods. The Racetech dealer I got the springs from said he thought that'd be all I'd need so to try that first. I put a PDS3 out back right away and it seems just right to me so far.

------------------
John Brunsgaard - JEB
01 KTM 400 EXC
99 KTM 250 EXC
99 KTM 200 EXC
98 KTM 125 EXC
98 KTM 380 MXC (gone)
96 KDX 200

[This message has been edited by jeb (edited 04-05-2001).]
 
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#8
Shaw - can I ask where you got .50kg fork springs?? Actually a better question might be 'why do you NEED .50 fork springs? Unless you weigh lose to 300 pounds (or have done something stupid - like install Gold Valves), there should be no reason to go stiffer than a .46kg.
 

Shaw520

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#9
Whip,
Holeshot has springs up to .54 (380pnd rider), They also have rear springs that go to 10.3
I'm 6'-1" 285 w/gear VetB.
I had .48's in my XR6 and were spot on.
The stock springs on the RFS are way soft, even for 170pnd aggresive rider. Hell, I got that by 100pnds, w/alot of upperbody weight.
Better to have high rate springs with very little preload dialed in, than have too low rate springs with alot of preload dialed in.

But,....Im having a hard time setting the sag on my PW80!





[This message has been edited by Shaw520 (edited 04-05-2001).]