Fork Setup - 00 KTM 300EXC

[KTM Mike]

I would like to get the forks on my 2000 KTM 300EXC fine tuned a bit more. As they are right now, I would have to say they are "not bad". I bought the bike used - have no clue on what volume and weight of oil is in the forks right now, and plan on changing it soon. As i have them currently the bike actually does quite well for me in sand and whoops - in fact i have been amazed with them in the typical Michigan sandy whoops - problem area is in the rocks and roots - somewhat harsh. If i back out the compression dampening about 2 or 3 clicks - decent in the rocks and roots, but way to soft for higher speeds and sand and whoops, and seems to blow through the stroke surprisingly quick. I am looking for (hoping for?)

--a bit better compromise set up that will improve rocks and roots performance without messing up how well it does in sand and whoops.
-- I would also hope to see if I could improve the cornering in real tight stuff as well.

I ride primarily Michigan trails and Enduros (D-14 throws in a few from Indiana for us as well), not the greatest of riders but steadily improving - "C Senior" class...or in my specific case what I call "slow old fart" class! 188 lbs without gear. Bike supposedly has one spring weight heavier on the rear than stock (so said the prior owner at least - how can I tell what spring is on it?), dont think springs in forks were changed from stock. As far as sag...ok - I will report back after some more homework and tell you what my sag is set at (like wise where my clickers are set right now). Seat of the pants feel...I would say the sag is certainly not to much...i might lean towards saying its on the lower end of the scale. Bike does not exhibit any headshake to speak of (though I shake my head often after hitting trees :confused: ). Forks are above the top clamp by about 5mm (ok...i will measure to be sure). My specific questions are:

- what weight and height/volume of oil recommended?
- any comments/thoughts on raising the forks up a tade more in the clamps to improve tight stuff cornering?
- at this point I dont want to go to the expense of a complete revalve at least until i have exhausted messing with the fork oil etc first.

Suggestions?????

 

[KTM-Lew]

Check e-bay for a set of .42 springs, the stock rate in the 4-stroke, and the cheapo re-valve kit. You can make a big difference in these for less than a 100 bucks. Go to e-bay motors-parts-motorcycle related and enter KTM. You should find what you need.

 

[KTM Mike]

KTM- Lew

thanks for the info. I looked on ebay for those .42 springs, but no luck did not find any...did come across a shock spring and the revalve kit. I have considered the revalve kit, but was thinking i should first get a sense of where I am with fresh "tuned" fork oil - then again...maybe i should just do both at the same time.

A couple other concerns...is the .42 necessarily what I need? I have not looked at the MX tech or other web sites yet to see what rate I need but will do so in the near future. ..does anyone have a recommendation based on experience if the .42s are appropriate for my weight and ability?

Also, if i do go for either (or both?) springs and or revalve kit...what oil weight and level is recommended? again perhaps that is where i should start?

I have read good feedback here on DRN for that revalve kit - certainly no complaints, and am considering them but wanted to dial in what i have first to get a better sense of what i need/want to change. I do have a race coming up in just a couple weeks with limited time for tuning before then... my concern is i do the kit...find i need tons of tuning from my current settings and end up actually worse off (temporarily at least) by the time the race comes around (not that it really matters to be honest...i gotta admit i am not a serious racer...nor a particularily good one...i only wanna have fun!) Can i reasonably expect to slap in the kit, change the oil and be better off with very limited tuning?

TIA for any replies!

 

[jeb]

Originally posted by KTM Mike
Can i reasonably expect to slap in the kit, change the oil and be better off with very limited tuning?

That's pretty much the way it worked for me. I'd adjusted the fork clickers just a little bit from stock before I put the kit in my 01 400E. I haven't touched a clicker since. Well, okay, I did go two clicks harder on the compression last week for a test but quickly went back and will leave them alone now. Why did I adjust it? Because I thought they were so plush, I might gain something by making them a little stiffer. I never noticeably bottom the forks so I don't know what I was expecting to gain.

Weight and height and how to set them is covered in the valving kit instructions. Generally, it's 140-150mm or 120-130mm, depending on the method you use to check the height. I've always used the recommended 5wt oil in my KTM forks.

The PDS shock springs have the number stenciled on. If it's not been worn off, you can read that to find out what spring you have on there. Stock was a PDS2. A PDS3 would be about perfect for your weight.

 

[KTM-Lew]

My thinking was you could use one .42 spring with your stock springs and then if you need to go with both. I think the re-valve, especially on the 2000 model, is a must-do. The used springs can be bought cheap.

 

[KTM Mike]

Ive been convinced on the revalve kit. Ordered it tonight. I will let you know how it works out for me! thanks for all the good advice. Once i have some miles in with the revalve then i will consider the suggestions on the springs. That revalve kit sure does sound like a "sure thing" for not much $!

 

[Magoo]

Hey Mike, as you know, I've a '00 300EXC too. I've done the ebay valve kit, and I can say it is quite nice! There is three "stack choices" you can choose from; I went with the middle (Stack 11). I was hesitant, too, because I really don't have a ton of experience to draw from when messing with suspension... but I can tell you I am very happy with it. The instructions are quite good, and I followed them carefully (including the oil refill and level procedure). I used Mobil One ATF, which has been recommended on this forum. It is important to have a in/lb torque wrench, as I've heard of some people having problems when reassembling the stack.
I went one harder on the compression than recommended, everything else is as recommended. I think the forks are much better at "following the terrain" now, and the rocks and roots are not as "jarring" as stock. Otherwise, the forks behave very nicely. I have set my sag at 1" on the forks, and 3.75" rear. The forks are at the first "ring" above the triple clamp.
Ummm, get it done before the Loose Moose!
See ya there!!

 

[KTM Mike]

I finally got the revalve kit installed. As others have said - the instructions are fantastic - easy to follow. Doing the work was quite easy - nothing that difficult at all. i was somewhat leery of it as i have never gone this far into a set of forks before - but having the guidance of these instructions made it a peice of cake - i would not hesitate in the future to do it again.


I just did a very short ride - to short to provide a fair assessment actually...but my preliminary impression is good. I did expect a more of a "wow" feeling of cush or something in the very start of the stroke ...and at the 1/3 to mid stroke range it actually feels a tiny bit firmer... BUT>....not harsh at all. I rode over several logs - seemed to deal with them quite well. I do need to mess with the clickers a bit to get a better feel for things. I started with the setting they recommend in the kit - my guess is I need to back off rebound about 2 clicks (think i had some packing going on) and i might even back off the compression a click or two just to see how it feels.
I went with stack 1, used ATF at 110mm (measured as per the instructions). My sag is at about 3.75 inches on shock, dunno on fork. I set the forks up to the second groove on the top with the hope of helping cornering manners a bit. I wonder what difference i might notice if i went with the 5 weight oil rather than ATF (which i understand is about a 7.5 weight). Hmmm gonna haveta play around a bit! I also did drill out the compression holes as suggested.

I will be doing some real riding this weekend (Magoo...see ya at the Loose Moose!) where i will find ample rocks, roots and logs and report back how the forks worked out!

 

[KTM-Lew]

Check the static and laden sag on the forks. If you have more than 30mm static but 50mm or less when laden then you can adjust the ride height by adding a little preload. Did that make sense???

If you have more than 50mm laden @ 30mm static then you probably need to go a little stiffer on the springs. If you know anyone that has a 2000 up 4-stroke see if they have changed springs and use 1 of their stock springs. You can then run the compression softer. The idea is to keep the bike up in the stroke with-out running the comp in. :cool:

 

[Magoo]

Mike, glad you got the kit installed! You'll be happy with it, I'm sure!
Better do some high speed runs with the forks at the second ring...unless you've got a steering damper, you had better be ready for some headshake!! For me the first ring was a reasonable comprimise. See ya this weekend! I'll be at the trail starting Thursday nite, it's lookin' SWEET!

 

[jeb]

Mike,
Glad you got the valving installed. A couple of thoughts, though. If you're undersprung, no valving will fix it. By being undersprung, which you are at 188 with the stock springs, you blow through the valving too quickly, the fork is going to dive on braking, etc. 42's, as has been suggested, would be a good choice for you.

If ATF is 7.5, that will make it harsher. I've always used 5wt fork oil in my KTM's and have been happy with it. I've not found any good reason personally to switch to ATF.

Let us know how the first real ride goes.

 

[KTM Mike]

I survived about 55 miles of the most sadistic rock infested, log infested, root infested nasties, some sections of sand, whoops (nothin like the lower Michigan whoops though), mud, hills and general "chop" that Magoo can help put together :p and gotta say the revalve did the trick for me.

At first I was not so sure, then as I was moving (at what i thought was my normally glacially slow pace) through a particularily rock infested section, happend to catch a glimpse of my Panoram's speed display - and much to my surprise was moving about 50% faster than I ever thought i might (putting me up to fast moving glacier speed) ....suddenly i realized what I WASNT feeling through the forks! Huge improvement. In the whoops - i really still need to try them on some real lower Michigan whoops (da UP just aint gott em like we do!) but i cant say it was "bad" there at all. On bigger "hits" - at one spot (Magoo you will know it...that power line section..one rare spot where my speed was up) i suddenly found myself much farther in the air than i planned on...landed a bit outta shape, front down - i dreaded the coming impact...but it soaked it up just fine, and away i went.

I left the clickers at 2 clicks out on compression and rebound from the suggested settings. I wonder if i should put the rebound back as the front was pushing a bit more than i would like. (wont rebound effect that?) I also do think i should do the 5 weight oil rather than ATF just to see what impact it has.

To Magoos comment re forks at second ring/head shake...the only head shaking i had was my own head...after a taking a few rock and soil samples in that first section! Given the layout of the course there really was not that many high speed sections...i will try it out locally and see.

On spring rate and sag measurements. I did measure it before the race - was at 30mm static, and at get this...50mm laden ...now i measured without my riding gear on, so fully geared up my laden would be a bit more than the 50mm. It sounds like I am darn close on spring rate, maybe just a touch light. It does dive more than before on braking it seems. Due to cost reasons (ie the wife says it aint in the budget) fork springs will have to wait...but i may sneek them in before to long.

To sum it all up....it works! I still will mess with set up a bit more, particularily the 5 wt - but so far i say it is well worth the $. One more qualifier...all these comments are coming from a slow guy...dumb enough to try enduro racing...far from fast, far from knowing what I am doing...but having a ton of fun while I am at it!

 

[Magoo]

Mike, It's hard for me to tell if you like the forks or the trail better?
It was good to see ya at the race. As usual, it's tough to get a chance to visit much. Hope you had a good time, and I'll catch up with you at some of the D14 enduros!

 

[KTM-Lew]

If you aren't having any bottoming problems your Ok on the springs. A little more pre-load will be needed as you get faster/more comfortable. Try going in 2 clicks at a time on the comp until you are sure its getting harsh on the trail junk. Then start backing out 1 click at a time till your happy. :cool:

I tend to run my rebound in a couple clicks more than most as the bike feels more planted in the choppy stuff.

 

[NO HAND]

Originally posted by KTM-Lew
Check the static and laden sag on the forks. If you have more than 30mm static but 50mm or less when laden then you can adjust the ride height by adding a little preload. Did that make sense???

If you have more than 50mm laden @ 30mm static then you probably need to go a little stiffer on the springs...

Numbers for the fork sag are not discussed very often and I think it's very interresting what you are about to explain. If 50mm ladden is the maximum, then what would be the ideal ladden sag? 40mm, 45mm? I guess it would be a number with a range of plus or minus 5mm.