steering/handling problems (DANGEROUS)

[kickbass]

Hello everyone. This is my first post on KDXRIDER, although I have been using the site for info and answers to my questions for a few months now with great success. You guys know your $h!# (stuff).

My name is John. I'm 44, and just getting back into riding off-road after an 12 year hiatus. Guess you can say I just had an itch that needed scratching. So I bought a 1995 Kdx 200h and rebuild it from the ground up to better than new. She runs great and looks awesome. BUT,,,, now here comes the problem..... The handling. Something is seriously wrong and I cant figure out what it is. The bike dose not track straight on flat level ground at low and moderate speed, (2nd and 3rd gear, haven't gone faster due to problem) It just wants to wander all over, (very "squirrely") and when I do turn, it really wants to keep turning. I have to push on the inside bar to keep it from going all the way to the steering stop. She seems to have a mind of her own. This problem is not just to one side or the other. I really need to figure this out. The bike is unsafe as is. (although I have been riding anyway )

To help narrow it down, here are things I have already checked or adjusted:

new tires (S12xc) front and rear
Tire pressure 10psi front and rear
forks are flush with top clamp
forks are not bent or twisted in clamps
steering head bearing has no excessive play and has proper tension
all other bearings (wheels and suspension) no excessive play and are properly lubed.
no obvious misalignment of wheels or handlebars
wheels are true within reason
steering stop is not bashed (which would be a sign of a previous hard crash)
I have adjusted rear race sag everywhere from 4 1/4 inches to 5 3/4 inches and everywhere in between with no luck.
front race sag is 1 1/2 inches

I'm stumped, and getting desperate. I am going on a riding vacation down in Louisiana next month, but the riding season is pretty much over here in Chicago, and I have run out of time to figure out this problem on my own and be able to test ride.

Any feedback would be GREATLY appreciated.


Thanks
John

[Rjcapt]

Try here:

http://www.thumpertalk.com/topic/827613 ... try8553705

http://www.thumpertalk.com/topic/775709 ... try7977522

There's lots of good info there.

Pete

[canamfan]

You don't say what rate spring you have in the front but if their to soft, you will be riding low in the front which will quicken the steering. i just put 42kg springs in the front of my h model, much better. Before i had the rear sag set at 5" to compensate for the sagging front end. i weigh 190 w/o gear it completely changed the way the bike handles, still quick but much more stable and a lot easier to loft the front wheel over logs. You might try running higher tire pressure, especially in the front like 14psi, those michelins really grip well.

[scheckaet]

are you riding sitting on top of your gas tank?
wrong spring rate also comes to mind.
are you fork binding?

[jetrep]

I"m with canamfan...try higher air pressure in both tires. Have the forks been rebuilt? Do they feel like they operate correctly when you squeeze the front brake and work them up and down?

<---another KDX owner named John in NE IL

[kawagumby]

If the suspension settings are reasonable, it is likely the forks have a mechanical problem. You may need stiffer springs...but it sounds more like it could be a broken fork spring or something binding that impedes rebound.

[SS109]

Nothing wrong with the tire pressure he is running. Make sure to follow the proper tightening procedure and to the correct torque for the forks and see if that helps. Anyways, I believe your problem could be with your spring rates for your weight and an imbalance between the two. What is your weight and what springs are you running front and rear?

[Goofaroo]

new tires (S12xc) front and rear
Tire pressure 10psi front and rear
forks are flush with top clamp
forks are not bent or twisted in clamps
steering head bearing has no excessive play and has proper tension
all other bearings (wheels and suspension) no excessive play and are properly lubed.
no obvious misalignment of wheels or handlebars
wheels are true within reason
steering stop is not bashed (which would be a sign of a previous hard crash)
I have adjusted rear race sag everywhere from 4 1/4 inches to 5 3/4 inches and everywhere in between with no luck.
front race sag is 1 1/2 inches

It sounds like you've been very thorough. Are you certain that the frame is not bent? Other than that, what about the steering head bearings? Did you replace them? I bought a BMW K100RT several years ago that was extremely wormy. It turned out that the steering bearings had worn to the point that they were "indexing" to the straight forward position. You couldn't really feel it with the bike assembled but once I removed the fork tubes you could feel the triple clamps "stop" in the straight ahead position. The races were worn in such a way that the steering head kind of locked in that position and required some effort to initiate it to turn. It made the bike completely dangerous and unrideable.

If that is the case, the proper fix would be to replace the bearings but a cheap and dirty fix is to remove the races and rotate them 90 degrees. This way the "indexed" portion of the race never comes into play because of the steering stops.

Other than that, you have presented quite a puzzle because you seem to be on the right track with setting up the bike. Low tire pressure, suspension settings, swingarm and linkage bearing slop, out of true wheels, etc. can certainly limit the fun factor but I can't imagine that any of those problems would cause the dramatic handling issues that you seem to have.

If you can, post some pics. A good side view of the bike on a stand might reveal something that you aren't seeing.

[scheckaet]

how's your rear suspension set up?
spring rate good for your weight or at least close enough?
maybe your sag is too much on the rear making your bike "nose dive"

[KDXGarage]

What is your weight in full riding gear? Do you have the stock springs in the forks and on the shock?

What terrain is it wandering on, pavement, hard packed dirt, soft dirt, mud, sand??

[Goofaroo]

The handling. Something is seriously wrong and I cant figure out what it is. The bike dose not track straight on flat level ground at low and moderate speed, (2nd and 3rd gear, haven't gone faster due to problem) It just wants to wander all over, (very "squirrely") and when I do turn, it really wants to keep turning. I have to push on the inside bar to keep it from going all the way to the steering stop. She seems to have a mind of her own. This problem is not just to one side or the other. I really need to figure this out. The bike is unsafe as is. (although I have been riding anyway )

Is this an accurate description or do your handling problems only appear when you are charging through the woods or hammering through some sand whoops? If it is unstable on level ground at low speed like you describe than I think you have a problem with the front end. I would check the steering head bearings very closely. Also, you didn't mention whether or not the bike is stock. Does it have the original forks and triple clamps. If someone put a different fork or triple setup on it it could certainly be the problem if the rake, offset, or trail has been altered. We need pics!

how's your rear suspension set up?
spring rate good for your weight or at least close enough?
maybe your sag is too much on the rear making your bike "nose dive"

Hey scheckaet,

I just noticed that you live in Edmond. I'm in Timber Ridge over at Danforth and Broadway. I'd really enjoy getting together and bullshitting each other over a couple of beers. I'd like to show you where I'm at on the KDX I'm rebuilding for my son and maybe pick your brain a little. I'm also looking always looking for someone to ride with and with riding season here I'm ready to hit the trail if you don't mind me tagging along. The older I get the harder it is to find someone to hit the trails with.

[KarlP]

It sounds like the front is riding way too low.

You can't really compensate for a way too soft a rear spring by increasing preload. It'll get all squirrely!

Your weight would be a good piece of information.

I used XR400 fork springs in mine. I think I went from the stock .35 (?) to .42? It was quite a bit stiffer and I was at 180 lb. It really needed it compared to stock.

Tire pressure is fine at 10-11 psi. Heck, I run 8.5-9.5.

[kickbass]

Hi guys. Thanks for all the replies. From the research I have done and all of your replies, I have decided the best next step is new Race tech springs front and rear. I weigh 225 without gear and have a habit of riding all the way forward on the seat. I don't know what spring rates are on the bike now, and don't even know who the p.o. was. The front fork spring spacers are not the stock units. It has pvc spacers about 4 inches long. I assume the p.o. tried to add preload with the pvc spacers.

I just ordered new front and rear springs of the appropriate rates for my weight and riding style from Race Tech using their spring rate finder. (.48 front and 5.4 rear) New springs will arrive Friday. Install Saturday. Test ride Sunday. Hopefully this will do the trick.

But now this brings up 2 new questions.
How Much race sag should I have on the forks?
And how long is the spring spacer supposed to be?

I truly do appreciate all the feedback, and I love KDXRIDER.net

I will post my test ride results Sunday night.

Thank all of you.

John

[imgC:\Users\john\Pictures][/img]

[kickbass]

OOPS. Let me try this again.
This is before the new tires, but all else is the same.

[scheckaet]

225 on stock springs and riding on the tank...I'd say look no further we may have a winner!

[SS109]

225 on stock springs and riding on the tank...I'd say look no further we may have a winner!

Yeah, if they are the stock springs, which they more than likely are, I completely agree!

[Goofaroo]

The bike dose not track straight on flat level ground at low and moderate speed, (2nd and 3rd gear, haven't gone faster due to problem) It just wants to wander all over, (very "squirrely") and when I do turn, it really wants to keep turning. I have to push on the inside bar to keep it from going all the way to the steering stop. She seems to have a mind of her own. This problem is not just to one side or the other. I really need to figure this out. The bike is unsafe as is.

I'm curious to see what the new springs do for you and I hope it fixes your problem-- but I find it hard to believe that your bike is rendered useless to the point you can't even get it out of 3rd gear on level ground because it has stock fork springs . I weigh about 230 and I've ridden all kinds and sizes of dirt and street bikes with stock fork springs and I've sat on them wherever I wanted to and I've never had one of them even remotely display the kind of handling terror you describe. It sounds like it is completely useless and unsafe. I don't know anything about your riding ability but if you're fairly quick you'll certainly benefit from the proper springs but I still think you may have another problem. If you could expand on your problem just a bit maybe we'll uncover something else that may be responsible for your "less than stellar" handling.

You said you rebuilt it from the ground up. Were you able to ride it before you took it apart? If so, was it handling hell or did it ride straight on level ground?

Does it just wallow slowly from one side to the other and is difficult to keep centered? While moving does it feel as though the centered position is a high spot and it is constantly requiring effort to keep it from rolling off to one side?

While you were riding it was someone holding your beer for you?

Are you exaggerating how bad it is or is it literally unsafe on level ground? If so, it sounds to me like the frame might be tweaked. Did you look it over closely while it was apart? Did you notice any cracks or alignment issues in the frame. Do the forks look true with the bike? If you put it on a bike stand does it look right? Have you measured the wheelbase?

It still sounds to me like you were very thorough putting this bike together and trying to troubleshoot the handling. If your different sag settings didn't make any noticeable difference in the handling and you were never able to ride it comfortably on level ground then I think there is a serious issue being overlooked.

The common consensus here seems to be that new springs will fix it so I'm probably wrong but the whole idea that a properly assembled KDX with stock springs can't carry a 220 lb rider safely across level ground doesn't seem feasible to me.

I'm very curious to find out what fixes it so please keep us updated. Hopefully you can get it handling perfectly before your trip.

[KarlP]

I hope new springs help with your steering issues

You'll have to fool arond a bit with the spacer length in the forks to get the right preload. I have always found that I like between 5 and 10 mm of preload in the fork and no more than 25mm preload on the shock spring. I'd try that and see what the sag numbers end up at. Search around on here, there is a procedure for setting fork spring preload.

I'd set your clickers to midpoints.

I've also never had much luck setting shock sag by a published or recommended spec. I usually set it to that spec and then go ride. Get the bike and rider fully warmed up and find a loop that takes 3 to 4 minutes and has plenty of uncomfortable bumps and roots and turns, etc. I leave the shock lock ring loose and take the bike around the loop a couple of times to get a feel for how it is acting as far as fore aft "attitude". If I think the back is high or low I'll lay the bike over and and give the shock spring a turn or two tighter or looser. Keep going on this process and I'll bet you'll find the sweet spot where it turns just right.

Then you get to play with clickers.....

[rbates9]

Has anyone else rode the bike and felt the same as you do about the handling?

I weigh about 230 give or take and rode on stock springs for a season plus and didn't ever feel that the bike was unsafe. I tend to ride all over the seat from the front to the back. I have to agree with Goofaroo that something doesn't seem right. Second to third gear seems a bit slow to have springs cause an issue on flat ground. I'm not saying that new springs won't help anything but it just seems odd that they could make a bike unridable. I too have rode many bikes that were too small for me and never felt that the springs were too soft making it unrideable. Land hard, yes, but to cause a wobble going straight on flat ground seems unlikely.

Hopefully new springs will take care of it and I would like to hear the results too.

[canyncarvr]

What a great question to get an answser to!



Oh. There isn't one.

Is it Sunday night, yet?