Race Sag - '02 KTM PDS

[KaTooMer]

I just killed the afternoon trying (unsuccessfully) to set the race say on my '02 KTM 300MXC. It's not rocket science, but I'm thoroughly confused. The rear spring is a PDS6 (260mm), which is the next-to-softest 260mm spring, according to the manual. I weigh about 170-175 pounds with all my gear on.

The smallest level of race sag I can get is 115mm, which is with the preload ring turned down so that there's about an inch of threads showing (probably more than recommended). At that amount of preload, it gets very hard to turn the preload ring. I assumed that the spring is too soft, so I swapped the shock from my '99 300EXC and tried it in the '02. The '99 uses a PDS2 spring, which is a 250mm spring that is stiffer than the PDS6. Stiffer spring should mean less sag, right? Apparently not, because the PDS2 had MORE sag on the '02 bike (about 125mm). The PDS2 works perfectly for me on the '99, and is set with 100mm race sag.

So I'm confused...the PDS6 is not going to work, nor is the PDS2. Seems very odd that the PDS2 works fine with the '99 but not with the '02. The bikes aren't that much different. I've not heard of anyone having problems with sag on the '02's. Any ideas?

Thanks.

 

[Fred T]

I believe you set your static sag on a KTM and then measure race sag. Static sag should be 25-28MM (not the listed 35MM in manual)

 

[KaTooMer]

Static sag is off the charts, too...can't get it below 50mm.

 

[Jeremy Wilkey]

Intresting stuff.. I think you may have a gas pressure issue, (posibly).. But what I don't understand is you have the spring down that tight and have 50mm of bike Sag?

Friging werid.. I read that 3 times, Its allmost like somethig is getting confused..

 

[shockdoc]

I hear ya Jer....I was like "HUH?" LOL




doc

 

[marcusgunby]

Check you measurements again with a helper-make sure the measurement is taken vertical-dont make the tape measure at a angle.Sit in the normal sitting position, head upwards.

 

[KaTooMer]

Here's some revised numbers, re-measureing from the left side (and some would say, the correct side) of the bike. About an inch of threads showing on the shock; 2 gallons of gas in the tank. I measured from just above the chain adjuster bolt, to the intersection of the rear fender and side panel (pretty straight).

On the stand: 23.5 inches
Bike only: 22 inches
Me on bike: 19-3/16

I calculate static sag at 1.5 inches, or 38mm, and race sag at 4-5/16 inches, or 109.5mm. That's getting closer....one other thing I didn't mention is that the bike has been ridden less than 5 hours, so the suspension is not completely broken in yet. Does that matter? A blown seal/loss of nitrogen would be pretty easy to see, and the shock seems to work O.K.

Thanks for your input.

 

[shockdoc]

Those figures sound a little better....I would just tighten your spring preload a cpl. more turns and you will be pretty close.


doc