02 KTM SX 48mm forks - disassembly hints or tricks

[James]

I am mostly familiar with Showa twin chambers and conventional cartridge forks.

We need to clean/replace my brothers fork seals and before I tear into them...I was curious if they came apart like most others (damper bolt, dust seal, seal retaining ring, pull apart quickly) or if there were any special considerations.

His manual didn't have instructions and I found some info on the KTM 43s on MX Tech but would like to extra cautious since it isn't mine. Can I just follow the instructions for the 43mms?

 

[marcusgunby]

The forks are very similar to the 43mm apart from the adjustable preload cap-you can back off the preload adjuster to loosen but its not ideal-best to make a correct tool to fit the cap. Also note the way the bushes come out behind the seals as they are not identicle.Use heat to ease removal of seals/bushes.

Some people are using the KX125/250 48mm seals as these dont leak like Wps.I have never done that mod so i cant help more on that issue.

 

[James]

Thanks Marcus!

Are the bushings easy to damage when yanking apart or are they relatively sturdy?

 

[marcusgunby]

the ring that sits under the seal tends to bend.You can flatten it again however.

 

[shockdoc]

You can also use the KYB slide & guide bush. The extra (2nd) guide bush is thinner though & has to be from WP. With a little heat like Marcus said tho they should come apart ok.


doc

 

[James]

Just to clarify, how do you apply heat.....do you just take a propane torch to the tube or do you use a heat gun? Does it discolor at all if using the torch? I assume that you only mildly heat the area near the seals but I suspect a hair dryer wouldn't cut it right?

Believe it or not...I forgot the simplest thing of all.....didn't order the fork seal driver. I had borrowed Gomer's for the last round of fork repairs and forgot to order my own. That's how it usually goes with me.

 

[Jeff Howe]

I thought 03 WP forks were the first ones to come with dual bushing setup. I don't remember these on the 02 48's I have done.

 

[marcusgunby]

I think shocknut is right-03 had the new bush-it was the 02 SXS that had them??

 

[shockdoc]

Yup you guys are right. I didn't see that it was an '02 at first. James....a small propane torch will work. Be carefull and it won't discolor your tubes.



doc

 

[mxbundy]

Hi guys,

Which KYB parts i nterchange with the WP stuff.
I am working on a brand new set of WP forks off of Thumbs new 03 200MXC.
This bike was brand new before dirtweek and the seals started leeking while we where there.
Here is the rub, the seals passed so much of the sand and mud that you could actually feel the sand rud off into your fingers from the seals after I got them out. In fact the bushings are wasted too, the teflon coating looks like it has been sandblasted and is really rough.
Now here is the rub, a new set of bushings will cost $160.00 :| at our local dealer. That is absurd!

So what bike or bikes will the KYB cross reference over to the WP stuff.
I take it that the 3rd bushing may have to come from WP.
Hopefully the KYB seals will hold up better too.

Anybody ahve any luck with the seal savers?


Bundy

 

[bclapham]

bundy:

for a start, are those forks 48mm? for bushings, just measure them and compare them to the ones on racetech's or mx-tech website, they give all the dimensions etc so you should be good to go.

 

[James]

DOes anybody else think KTM manuals are useless for suspension work??

Do any of you experts have the torque values for the fork cap lock nut, the base/damper bolt, and know the standard oil level range??

I haven't taken the second leg apart yet and I might be able to guestimate the level by measuring what is in there and adding a bit for the leakage.

Thanks as always!!!

 

[marcusgunby]

Manuals are poor IMO.
Fork caps i only snug them down-hardly tighten them at all.
base valves 25lb/ft.
Air gap 140mm to 110mm i would guess.

 

[bclapham]

i worked on a 02 125sx and it came with 2 manuals, one for the biike and one for the WP suspension. maybe it is missing? luckily, i didnt have to work on the suspension!;)

 

[marcusgunby]

My 99 wp PDS manual was good-the ktm manual wasnt.

 

[James]

Well Good News!!!

Turns out he DID have a separate manual that he DIDN'T THINK was important til after we spent an hour or two one the web looking for this stuff.

Oil level is 110-150 mm
Base Valves were 25 NM (meant to check the conversion to ft/lbs)
Fork Cap to damper rod is 20NM - we didn't have a wrench to fit the thin slotted lock nut so that required a trip to Sears. Ended up buying some pliers with hexagonal teeth that were 7.5 mm thick.
Using the preload adjuster to remove the caps was fine because they were just snug. We only had to count the turns to get it back to the right spot.

I was real pleased about the lesser torque requirments of the KTM. I am used to 51ft lb base bolts and 100 ft lb steering head nuts on the Hondas....I hate twisting bolts that hard. I find the showas to be a bit easier but maybe that is just because I have worked on those more.

Thanks again for all of your help....hopefully I can help somebody else on these now.

 

[Jman271]

This is a link for complete dis-assemble and re-install for the 48mm WP forks, w/ trq specs, oil height, etc. You will need Adobe to open, sorry for not posting sooner, just saw this post.

www.karlstrommotor.se/bilder/wpis.pdf

 

[James]

That is exactly what I was looking for.

That is even better than the WP manual that came with the bike!

No need to apologize...it will come in real handy next time.

THANKS!!