Jump to content
Sign in to follow this  

how do you set sag on forks 43 wp 1 520mxc??

Recommended Posts

Originally posted by bultaco290:

How are you guys setting the pre-load on these wp 43's Is it with pvc spacers like the honda's use?

Bultaco290 - you can buy the spacers from your local KTM dealer or just make your own,

like I do, out of PVC. Ideal static should

be between 25-35mm.

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

tbob

what size pvc and how big do you slit it?? the white pvc I guess it doesn't matter, one more thing how long a piece of pvc equals how much sag or does it depend on your spring rate?

Share this post


Link to post
Share on other sites
Originally posted by bultaco290:

tbob

what size pvc and how big do you slit it?? the white pvc I guess it doesn't matter, one more thing how long a piece of pvc equals how much sag or does it depend on your spring rate?

Bultaco290 - ya don't put a slit in it - you unscrew the cap from the damper rod. and then

place you spacer between the existing 2 spacers that are in there. If your running

stock springs you'll probably need between

12-15mm of preload to get the correct sag. I've only added 10mm so far and my static is still at 40mm.

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

tbob,

one more quick question; where do you measure the forks for satic sag the handle bars? or something fixed like that? I've got 46's sorings in mine I think I will still try 10mm

I've got to do something this weekend while doing alittle jumping I landed on a rock coming off a pretty big jump that I was bottoming hard on and I destroyed my skid plate... I'm sure glad I was useing one..

Share this post


Link to post
Share on other sites
Originally posted by TBob:

If your running

stock springs you'll probably need between

12-15mm of preload to get the correct sag. I've only added 10mm so far and my static is still at 40mm.

Does that mean you've added 10mm of extra preload ie: a 10mm peice of PVC or 10mm total preload ie: stock amount plus x mm new?

Do you do yours by taking off the handlebars , unscrewing the cap and lifting out? ie. leave forks on bike?

Share this post


Link to post
Share on other sites

max

yes it is on top of the preload spacers that are already there.... yes you can do this with the fork on the bike, but you willl need to losen the pinch bolts on the triple clamp

Share this post


Link to post
Share on other sites
Originally posted by bultaco290:

tbob,

one more quick question; where do you measure the forks for satic sag the handle bars? or something fixed like that? I've got 46's sorings in mine I think I will still try 10mm

I've got to do something this weekend while doing alittle jumping I landed on a rock coming off a pretty big jump that I was bottoming hard on and I destroyed my skid plate... I'm sure glad I was useing one..

Measure you sag from the axle to the top of the fork(or handle bars) whatever works for

you. First measurement fully extended the second with the bike under its own weight

the difference between the 2 is your static.

This will not help your bottoming much- you'll need to raise you oil level to help with your bottoming issues.

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

Bultaco290- I made 30mm spacers last night

and put them in - my static sag is now

30mm right were it should be. I have stock

springs. 30mm of preload is double what KTM

puts in them.... I wonder what they're thinking? :)

Just to clairify - that's 30mm of preload total.

picture.JPG

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

[This message has been edited by TBob (edited 07-26-2001).]

[This message has been edited by TBob (edited 07-26-2001).]

Share this post


Link to post
Share on other sites

Hearing you guys talk about tuning the suspension setup on these bikes; I guess I should do something. I'm sure my '01 520exc needs to be firmed up a bit because I'm in the 210 lb range but I haven't done a thing yet. All I've done is ride. Sure; it seems soft but I don't jump that much. I just ride in the mountains and trails at a pretty good clip around here and it's obvious that I'm using all of the travel I have but I've never bottomed it hard.

So you guys think it's worth going to the trouble and expense of doing all of this? I guess I'd better start getting familiar with all of the suspension terminology you guys use because some of it goes over my head. I guess I'd better also buy a metric tape measure too. I've gathered that, at a minimum I'll need these PVC spacers in my forks and a firmer spring in the rear? Anyone out there about my size already gone through this process and figure out what works and what doesn't?

By the way, there is a pretty good article on setting the fork oil level on the KTM USA web site. The URL is http://www.ktmusa.com/ugvol11no1/ug16.htm

Share this post


Link to post
Share on other sites
Originally posted by Arbellspi:

Hearing you guys talk about tuning the suspension setup on these bikes; I guess I should do something. I'm sure my '01 520exc needs to be firmed up a bit because I'm in the 210 lb range but I haven't done a thing yet. All I've done is ride. Sure; it seems soft but I don't jump that much. I just ride in the mountains and trails at a pretty good clip around here and it's obvious that I'm using all of the travel I have but I've never bottomed it hard.

So you guys think it's worth going to the trouble and expense of doing all of this? I guess I'd better start getting familiar with all of the suspension terminology you guys use because some of it goes over my head. I guess I'd better also buy a metric tape measure too. I've gathered that, at a minimum I'll need these PVC spacers in my forks and a firmer spring in the rear? Anyone out there about my size already gone through this process and figure out what works and what doesn't?

By the way, there is a pretty good article on setting the fork oil level on the KTM USA web site. The URL is http://www.ktmusa.com/ugvol11no1/ug16.htm

Well - I don't think you'll be able to set the proper sag with a #3 I weigh 230 and w/o gear I can't and I've got the pre-load as much as you can go and still have 20mm of static sag. But I traded my 2 for a 3 so the price was right. If you go with a 4 you'll definately need to go with heavier springs.

I would guess 44's with the right static and oil hieght would be a balence combo with the 4 but I haven't gotten that far yet. I've been able to get things balenced with the 3 using the stock 42 up front.

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

Stacking alot of preload to your stock springs is not the proper way to set your spring rate. Your weight and your riding abilities are direclty related the the spring rate that will best suit you.

The stock springs in these RFS are set for a 175pnd non agressive rider,(my opinion of course!) If you fall in this 150-180 pnd range, you could probaly benefit from playing with the spacers,(PVC). But if you're over that and get agressive, then get the proper rate spring for your weight and ability, and these bikes become supreme handlers! Check out KTM Tech (HoleShot) give them your info,(weight and riding ability) and they will reccomend proper springs. Thats what I did to my 520 and the difference is awesome. Just be prepared to do both ends at the same time, $125 for the front, and $125 for the rear spring. Well worth the $250. BTW, changing the springs is VERY easy to do.

Share this post


Link to post
Share on other sites

Servus TBob,

Thickness of the spacer is NOT equal preload. Stock preload on the RFS is 6mm. KTM says max. preload is 15mm, anything more will possibly damage your fork and springs and is not the proper to setup your forks. Get stiffer springs!!!

Michael

Share this post


Link to post
Share on other sites
Originally posted by Shaw520:

Stacking alot of preload to your stock springs is not the proper way to set your spring rate. Your weight and your riding abilities are direclty related the the spring rate that will best suit you.

The stock springs in these RFS are set for a 175pnd non agressive rider,(my opinion of course!) If you fall in this 150-180 pnd range, you could probaly benefit from playing with the spacers,(PVC). But if you're over that and get agressive, then get the proper rate spring for your weight and ability, and these bikes become supreme handlers! Check out KTM Tech (HoleShot) give them your info,(weight and riding ability) and they will reccomend proper springs. Thats what I did to my 520 and the difference is awesome. Just be prepared to do both ends at the same time, $125 for the front, and $125 for the rear spring. Well worth the $250. BTW, changing the springs is VERY easy to do.

Shaw520 - I never said it was the proper way to set spring rate! What I did say was the bike comes under pre-loaded from the factory- and 60mm of static sag is way too much. Even for a 175lb non-agressive rider. This has nothing to do with spring selection- in fact I allready know that 44's up front with 4 in the back would be alot better setup. But again my point here is that 60mm of static sag is WRONG! and of coarse your forks felt worlds better with the heavier springs - because you had less static sag you were further up in the stroke were you should be.

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites
Originally posted by Drehwurm:

Servus TBob,

Thickness of the spacer is NOT equal preload. Stock preload on the RFS is 6mm. KTM says max. preload is 15mm, anything more will possibly damage your fork and springs and is not the proper to setup your forks. Get stiffer springs!!!

Michael

Yes Michel thickness of the spacers does equal preload - tell me how else you plan on adding pre-load? My bike came from the factory with 15mm. - Don't know where your finding your info but you are INCORRECT!

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

TBob, I'm not trying to bash you you on this, I'm trying to help you. If you dont want the help then tell me so, and I'll move on.

First of all; static sag is not as crucial as race sag, every riders' weight is different, so setting static sag will get you no where. Your race sag should be set at 90mm, and the only way to acheive that is by getting the correct spring rate for your weight. I agree that that 60mm of static sag is way too much, all thats telling me is that you stock springs are shot. Adding preload to the stock springs to acheive proper race sag will ruin the proper funtions of your forks. Adding too much preload to the springs could cause them to "stack" at full compression and destroy your forks.

A rider weighing 190pnds may have 30mm of static sag with the proper spring set up, whereas, a rider weighing 220 pnds may have only 10mm of static sag with proper spring set up for him. Neverless, this is not important.

To get the proper spring rate for your weight you will need to achieve 90-110mm of race sag, and possibly slightly less in the front, with you dressed in gear, on the bike in riding position,(done with the help of a freind to hold you up).

If you want to e-mail me and tell me your weight and riding skills, I can tell you what spring rates you should be using.

Again, I'm just trying to help, you wont believe how well these RFS's handle with proper springs installed.

Share this post


Link to post
Share on other sites

Oh no....race sag vs static sag again. :)

90mm = how many inches again? I gotta get a metric tape, all this math stuff is tooo hard. :D I hope the forks don't mind me putting good old standard size pvc spacers in them, I could not find any metric pvc.

Okay on a serios note, I put 48's in the forks on my 520. Now I have about 90mm race sag with the stock amount of preload spacers. Static is about 20mm. It sucks...the front end is like a rock on the small stuff and slow uphills. I get bounced all over the place as the only suspension action is with the tire. It is better on the fast hard hitting stuff, but I think preloaded 46's with more oil level would suit me better.

Maybe it is just stiction and time will help.

See ya all later :D

------------------

Pretend it's flat and give it the gas.

Share this post


Link to post
Share on other sites

Servus TBob,

Adding and measuring preload are two different things. If you have a 15mm spacer and add a 6mm spacer you added 6mm of preload but in most cases don't have 21mm of preload. To put it differently: If you remove the spacers from your fork, does it have 0 preload - no. There is a gap between the fork cap and the springs!

In the back of you manual there is listed how much preload you should have from the factory, which for a 2001 KTM 520EXC is 6mm.

Michael

Share this post


Link to post
Share on other sites

YZCourt, You didnt mention your weight so its hard to make an educated guess. Oil weight, oil level, and compression clickers play a big role in fork harshness. I'm 6-1 260 pnds and running .50's in my forks with 3-5 weight oil set at medium height, compression clickers set at 4 from the least (-), and it siuts me fantastic. In fact, my riding buddy (180pnds and rides a 520 with stock springs), rode my bike and couldnt beleive the difference in the way it handled. He is currently getting new springs for his.

Share this post


Link to post
Share on other sites
Originally posted by Shaw520:

TBob, I'm not trying to bash you you on this, I'm trying to help you. If you dont want the help then tell me so, and I'll move on.

First of all; static sag is not as crucial as race sag, every riders' weight is different, so setting static sag will get you no where. Your race sag should be set at 90mm, and the only way to acheive that is by getting the correct spring rate for your weight. I agree that that 60mm of static sag is way too much, all thats telling me is that you stock springs are shot. Adding preload to the stock springs to acheive proper race sag will ruin the proper funtions of your forks. Adding too much preload to the springs could cause them to "stack" at full compression and destroy your forks.

A rider weighing 190pnds may have 30mm of static sag with the proper spring set up, whereas, a rider weighing 220 pnds may have only 10mm of static sag with proper spring set up for him. Neverless, this is not important.

To get the proper spring rate for your weight you will need to achieve 90-110mm of race sag, and possibly slightly less in the front, with you dressed in gear, on the bike in riding position,(done with the help of a freind to hold you up).

If you want to e-mail me and tell me your weight and riding skills, I can tell you what spring rates you should be using.

Again, I'm just trying to help, you wont believe how well these RFS's handle with proper springs installed.

Shaw520 - I appreciate your post but after

doing this for 25 years I have a pretty good handle on what I'm doing - My front springs

are not shot - they are new. I also relize that adding too much preload will cause "stack" as you put it - I've always called it coil bind. I also realize that I would benifit from slightly stiffer springs. But I've also learned from pass experiance

not to be too agressive on the spring size because it can cause thing to get worse if you go to stiff. I also believe that for a suspension to work properly static sag is one of the most overlooked issues - I would not want to ride a set of forks with 10mm of static sag, I know how well they would work.

I would be interested to hear what springs you think I should run - I weigh 235 w/o gear

and would rank myself fast intermidiate-expert depending on the event.

Thanks,

------------------

TBob

"01" KTM 520 EXC

Mesa, AZ

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×