Suspension adjustments...

[MtnEX]

Guys, I went out yesterday and got my 400EX in the air several times... much more jumping than I typically do...

It has become painfully obvious I've got to do some adjusting on this machine. I really didn't realize how off it was until now...


What is happening is when I go into the face of a jump, my front end really soaks it up bigtime... But when I launch my rear is kicking up high.

It's to the point I can't seem to correct it well enough to always get a good landing.

I'm thinking maybe my rear rebound is super fast?


Can you guys give me a starting point to work from to help me work this issue out of it?

I'm 200 lbs...

[bigbad400]

are you on stock shocks? the rear has 3 ways of adjusting it, ride height, rebound and compression, i cant remember wich is wich but the top and bottom of the shock has some adjusting skrews thats rebound and compression, the adjuster on the spring is your ride height. dont know if that helps alot but only other advise i can give is get elkas, i love mine and they come mostly set up. i only had to adjust the ride height on mine and they are perfect.

[F-16Guy]

I think your problem is more related to throttle control. Use a little more throttle off the face of the jump. A lot of people have a tendancy to let of a little when they get to the face, which causes the back end to launch high. Ideally, you want to give a little blip of throttle up the face to keep the front end up and make you fly level.

400ex's are notorious for this "buck" you speak of. Actually the 450r is like that too. It takes some adjustment of the rear shock. I had this problem too.

The rebound screw is on the bottom of the shock. Turn the rebound down some. It helped with me.

That's about all you can do then it comes to technique. When you're about to hit the jump, standing up, lean back quite a ways. So standing and leaning back. Right as you're about to leave the jump blip the throttle.

[Gibson]

like F-16 said, dont let off the throttle, if any thing give the throttle a little "pop" right before you leave the ground.

you can adjust it all day long and use throttle control all that you want, but that buck will never go completely away...the key is to get the rear shock revalved along with a rear link from gt thunder...it makes a world of difference, it is well worth the price...

Originally posted by speedyquad
you can adjust it all day long and use throttle control all that you want, but that buck will never go completely away...the key is to get the rear shock revalved along with a rear link from gt thunder...it makes a world of difference, it is well worth the price...

You say that a lot, but my suspension is completely stock and I have no more buck problem.
I think maybe rider weight might have something to do with it. Im a heavier guy and dont have a problem.

[MtnEX]

I'm 200 lbs.... are we close?

If so, what are your settings?

Originally posted by DMC-4OOEX
You say that a lot, but my suspension is completely stock and I have no more buck problem.
I think maybe rider weight might have something to do with it. Im a heavier guy and dont have a problem.

lonestar_r had the buck and he is 250ish...

rider ability don't have anything to do with it either...it is that The stock linkage on most bikes sets the travel of the shock too high in the chassis and has too steep of a progression rate, thus making the rear end kick up very harsh when you hit a sharp object or come up just a hair short on a jump where the rear tires just clip the down side of the landing and you end up going over the bars. To solve this, you can either raise the top shock mount on the frame by cutting and rewelding it or buy the GT Thunder linkage. The new linkage has a lot lower progression rate so it doesn't make your shock too stiff too fast. On a positive side, it also lowers the ride height by about 1 1/2" for better cornering stability.


like i have said before, until you have ridden with one, you will not realize how much of a difference it makes...

[F-16Guy]

I'm about 205 plus or minus, and I'm running the stock shock with just a couple clicks more compression and rebound.

You have to be careful because I think the rebound (bottom adjuster screw) is reverse for adjustments. CCW is actually more firm, while CW is softer. You'll want to turn the top adjustment a few clicks CW and the bottom adjustment CCW a few clicks to firm things up.

I haven't noticed any bucking from my stock shock, but I've never ridden a high-end aftermarket setup, so maybe I'm just used to it. I've never had any problems with getting thrown off of jumps funny, though. Believe it or not, my stock shock hasn't even been serviced, and it still feels as good as my wife's low-hour 400ex. I may have it done in the future, but I have other things to spend money on right now, and it isn't leaking, so I'm going to leave it alone.

[F-16Guy]

Originally posted by Gibson
like F-16 said, dont let off the throttle, if any thing give the throttle a little "pop" right before you leave the ground.
Yup, gotta give it a little blip in most cases. Same with a bike.

Originally posted by MtnEX
I'm 200 lbs.... are we close?

If so, what are your settings?

about 220-230

[F-16Guy]

Originally posted by speedyquad
...rider ability don't have anything to do with it either...
I disagree with that. People that are just learning to jump almost always have trouble with throttle control. If you don't know how to use the throttle off the face of a jump, the best suspension in the world won't keep you from being nose up or nose down once in a while. It's something that just takes practice and an eye for how and when to apply or not apply throttle for a particular jump. Some lips require more throttle, and some you can almost coast over. It just depends.

[MtnEX]

Originally posted by DMC-4OOEX
about 220-230

You're a little heavier than me, but close enough to give me a start...

Where are you set at... I wanna compare to the other guy... and where mine is.

Originally posted by MtnEX
You're a little heavier than me, but close enough to give me a start...

Where are you set at... I wanna compare to the other guy... and where mine is.

Honestly, I'm not too sure. I did it a long time ago. All I know is I didn't really count turns, I just adjusted it slower a bit and went from there.

[MtnEX]

Originally posted by F-16Guy
I think your problem is more related to throttle control. Use a little more throttle off the face of the jump. A lot of people have a tendancy to let of a little when they get to the face, which causes the back end to launch high. Ideally, you want to give a little blip of throttle up the face to keep the front end up and make you fly level.


Originally posted by Gibson
like F-16 said, dont let off the throttle, if any thing give the throttle a little "pop" right before you leave the ground.


Originally posted by speedyquad
you can adjust it all day long and use throttle control all that you want, but that buck will never go completely away...the key is to get the rear shock revalved along with a rear link from gt thunder...it makes a world of difference, it is well worth the price...

You can be balls to the walls and it will still do it the way mine is right now...

The front absorbs and the back kicks up.

I'm glad I never hit a tall set of whoops, like MX style on this thing.... because a feller would be dead meat at first contact after hitting the first one.


If I can't adjust it out, I will get a GT Thunder link. I will have to have my PRM skid modded though, or go to something else I bet...

I'll do it 'IF' I'm going to keep a 400EX around.

[MtnEX]

What should the ride height be fellas?

I think part of the problem is mine is too HIGH.

Never realized it because it feels low.

[procircuit406ex]

Originally posted by speedyquad
lonestar_r had the buck and he is 250ish...

rider ability don't have anything to do with it either...it is that The stock linkage on most bikes sets the travel of the shock too high in the chassis and has too steep of a progression rate, thus making the rear end kick up very harsh when you hit a sharp object or come up just a hair short on a jump where the rear tires just clip the down side of the landing and you end up going over the bars. To solve this, you can either raise the top shock mount on the frame by cutting and rewelding it or buy the GT Thunder linkage. The new linkage has a lot lower progression rate so it doesn't make your shock too stiff too fast. On a positive side, it also lowers the ride height by about 1 1/2" for better cornering stability.


like i have said before, until you have ridden with one, you will not realize how much of a difference it makes...

Listen to this guy^^^ He obviously knows what he is talking about. The GT Thunder conversion is amazing, and is a night and day difference over the TRASHY stock rear suspension. The link itself is a huge improvment.

[procircuit406ex]

Originally posted by MtnEX
What should the ride height be fellas?

I think part of the problem is mine is too HIGH.

Never realized it because it feels low.

There is no magic number. GT Thunders website does/did have alot of info on ride height

EDIT - go to.... www.gtthunder.com scroll down to the suspension q&a's its the first one

ride height should be between 7.5 to 8 inches at the back of the pegs(with rider weight in a standing/attack position) with the front being about .25 to . higher(measured 22 inches forward of the point that the rear was measured. front will need to be measure the same way on both sides...

[procircuit406ex]

Thats about where mine is.

[MtnEX]

OK, with me on it, here is my ride height...

Rear (@ peg)........ 8 3/4"

Front (@ a-arm).... 9 1/2"



I never thought it felt that high, but it is when measured. I'm thinking there is too much preload on the springs... which would mess with the progression on the spring.

[MtnEX]

Well, I have fooled around here, and did a lot of thinking...

I think what I am going to do next is try lowering this bronco down as low as I can get it. I want to see very few threads on top of the preload rings.

Then I'll check it and see where it puts me.

I don't air it out big... all I need it to take without bottoming hard is XC style jumps... not big MX landings.


Best I can tell, I have lowered the compression all the way and slowed the rebound as slow as possible. I can sure tell some difference, but not as much as I expected from that radical of a change.


I think the ride height has got to come down so the spring tension isn't as high.

So I think they are certainly right about the "progression" part of it.

like i said, you can mess with it all that you want, but that buck will not go away until you change the linkage. not to bash on dmc, but he has never ridden one with the new linkage...i noticed it, but did not realize how bad it was until i rode a machine that did not buck like the stock 400ex(450r also). after that, it was very noticeable, and annoying. once i changed out the link, i was a lot happier...

my guess is that you notice this buck more after having spent some time on your kawi...

[MtnEX]

Originally posted by speedyquad
like i said, you can mess with it all that you want, but that buck will not go away until you change the linkage. not to bash on dmc, but he has never ridden one with the new linkage...i noticed it, but did not realize how bad it was until i rode a machine that did not buck like the stock 400ex(450r also). after that, it was very noticeable, and annoying. once i changed out the link, i was a lot happier...

my guess is that you notice this buck more after having spent some time on your kawi...

Well, to be honest with you I always noticed it had some buck when woods riding... but nothing I couldn't live with. So does the TRX450R.... both fall short of the old 250R Pro-Link rear.

I didn't realize how bad the buck was until I started jumping the 400EX... which is not something I commonly do since I started riding again.

I've also been on a couple of rides on open mountain logging roads that have huge water breaks pushed up.... Pretty good jumps also...

Anyways, even on these smaller jumps it was all I could do to keep it corrected. On a long downhill section with several of them, it was all I could do to keep it under me and keep up with a little 300EX... which has no such troubles.

Rolling downhill into jumps is hell.

[MtnEX]

Well, I cranked my preload off.

I had room to move it way up. So I set the lock ring with about 3 threads showing above it and cranked it up to there.

I turned the compression all the way soft and the rebound all the way slow. Well I turned them 99% there because it's not good to go all the way. I'm surprised there are no clicks.


Purely guessing here, but as far as my seat of the pants can tell, I'd be surprised if the actual ride height dropped 1/4" with all that adjustment, even though I did greater adjustment than that at the spring.

We will see though, once I can get it measured.
I'm sure the front will need to come down too.

[MtnEX]

Well, I didn't take measurements yet...

I just got back from taking it out on a ride.
I didn't go back to the same place though.


It's certainly better now, but not the extreme difference in feeling I was expecting. I mean I didn't even break out the screw driver and kick the adjustments up on anything.


It still soaks up in front and kicks in the back. Not as bad, but it kicks.

I actually hit one little hump out there trying my hardest to get a good little hop out of it. The @ss end kicked up hard enough to bash the seat into me in an aggressive stance and knock me off the pegs.

I don't know what to think... lol...

Right now, when I push down on the quad, it comes back up slow. But I tell you... during riding it feels like the spring winds up tight in the lower part of the travel and snaps out when it gets a chance.

To test this theory, I got up on the grab bar with my feet, then let my toes slip off quick... and there is where I saw the quick snap back.

I'm not sure where to go from here to get the best out of it for now.

Like I don't know if this is one of those shocks that has cross-effect on the compression and rebound adjustments, etc...

I'm thinking of going to the trouble to try using up those last few threads on top of the spring... and then I don't know where to go from there on the shock adjusters......

can you send me a video of it "snapping back" with you standing on the grab barm and i'll do the same with my gt thunder linked ex for comparison...

[powertechn2]

mine used to buck, even after doing some suspension work, i switched wheels and tires, and it actually smoothed it out, esp in the whoops, before it sucked major.

im not a big air jumper, so i dunno if it really made that much of a difference there.

[MtnEX]

Originally posted by powertechn2
mine used to buck, even after doing some suspension work, i switched wheels and tires, and it actually smoothed it out, esp in the whoops, before it sucked major.

im not a big air jumper, so i dunno if it really made that much of a difference there.

I'd hate to get in tall and deep whoops with mine. I'd hit the first one, buck, go in nose heavy and faceplant immediately after the front tires hit... or end up bucked off.

I'm not a big air MX jumper anymore either...
Glad I never tried a serious MX track out on this thing....

[MtnEX]

Originally posted by speedyquad
can you send me a video of it "snapping back" with you standing on the grab barm and i'll do the same with my gt thunder linked ex for comparison...

Yes I will get some video first chance I get.

[powertechn2]

Originally posted by MtnEX
I'd hate to get in tall and deep whoops with mine. I'd hit the first one, buck, go in nose heavy and faceplant immediately after the front tires hit... or end up bucked off.

I'm not a big air MX jumper anymore either...
Glad I never tried a serious MX track out on this thing....


most of the trails i ride are normally really whooped out, esp in the last 2-3 years, just seem to get worse, never gets any better lol

there are a few counties where you weren't allowed to drive on the side of the road, so you had to ride in the "ditch" basically, and it would be like 3 miles of whoops, 24-36 inches deep about 3-4ft apart.
after tire swap, it really lessened the amount of them that would end up being a nose dive into.

i went with pure sport bandit 20inch xc tires on 10 inch wheels vs the stock size.
at first i had the 6ply's, but they were A. really heavy, and B. kept going flat, i normally run like 3-4 psi, and after half hour would be at 0 psi, had one actually pop the bead in the middle of the ride, but they were wider than the wheels, and i had no choice but to keep riding. the place i bought didnt wanna warranty them cause i had rocks in one, but they wouldnt hold air, and the 6 plys also vibrated something fierce, esp towards the top of 4th and 5th. the 4plys have been great, dont hook that well in sand, but they handle whoops and wet sand and hard pack good.

[MtnEX]

I'm running Holeshot HD rears...





I did not get the video today, but a buddy did watch me cross a little hump that kicks it around.

He said it looks like it compresses to very low in the travel, almost like it is bottoming... and then it just kicks.

I know it is not bottoming out, but I do think I will extract the last bit of drop I have in preload... and then try adding compression a little at a time, just for the hell of it.

[MtnEX]

Well... I finally have the ride height settled back out with the frame rake more where it ought to be.

I am at 8 1/2" and 8 3/4" I think.

That's as low as she goes.


I will have to ride it some more before I decide where the front feels best at for cornering and front tire bite (steering quickness).

I'll try to mess with it a little more and see where I'm at on the bucking... and get some video now....

Originally posted by DMC-4OOEX
400ex's are notorious for this "buck" you speak of. Actually the 450r is like that too. It takes some adjustment of the rear shock. I had this problem too.

The rebound screw is on the bottom of the shock. Turn the rebound down some. It helped with me.

That's about all you can do then it comes to technique. When you're about to hit the jump, standing up, lean back quite a ways. So standing and leaning back. Right as you're about to leave the jump blip the throttle. my 450r doesnt buck. ive never seen a 450r buck. i make all my jumps like 10-12 ft long and not 1 ft long so it doesnt buck.:rolleyes: