Plushness in suspension

karlp · Feb 28, 2003

How can I improve the "plushness" in my suspension?
Compared to my other bike ( I won't name names) I can feel every twig and pebble. It feels like most of the harshness is from the rear suspension. I have installed '97 xr 400 springs in the forks, enormous improvement!
I've played with the front and rear clickers a bit, set the front and rear sag. The bike really handles nicely and the suspension does work well. After a couple of hours of getting it though, the little stuff is getting to me. Any ideas?
2002 KDX 220

jaguar · Feb 28, 2003

Lower your tires air pressure to 12 pounds and don't be so finicky. At your age I would of died to have a bike as good as a stock KDX.

Robcolo · Feb 28, 2003

THis is typical of the KDX --It's made to go slow [very slow] and soon as you get out of second gear the suspension can't keep up. The harshness you feel pounding your hands & arms is excessive High Speed Compression Damping. You can't "tune" HSC with the "clickers" --the only remedy [I've found] is to install Gold Valves - and they've eliminated it almost entirely. You might get just a bit of relief by installing an ultra-light fork fluid, but I doubt you'd notice much difference.I tried Silkolene 2.5W and was still unhappy. The oil holes [ports] in the stock valves are so tiny that it takes very little flow to "lock" them up. Maybe someone out there will try drilling out the stock ports & removing a couple shims and see if this problem can be solved without having to spend $150-$200. The stock rear spring is too stiff for many riders and can firm up the back end too much.

karlp · Mar 3, 2003

My age, Jaguar? Greater than 30, less than 50. I agree with your point, but for a different reason. I'm running 8 pounds front, 10 pounds rear.
I've still got the stock oil in the forks. It seemed quite thick when I changed springs. It is due a change.
However, most of the harshness seemed to be from the rear. I'm 175 w/gear. I've got the rear sag set at 92 mm. Maybe 100?

Karl

canyncarvr · Mar 4, 2003

What is the preload on the fork springs?

Fork oil level?

When was the shock last serviced?

It's a matter of personal opinion...but I hated a 95mm sag setting! 100mm is fine.

What's your free sag?

spikes · Mar 5, 2003

I FITTED RACE TECH GOLD VALVES AND THEY ARE GREAT. FORKS = FMGV 2040 AND SHOCK = SMGV 4401 VALVES. AS SOON AS YOU GO TOO FAR WITH THE LIGHTER OIL AND DAMPING SETTINGS YOU`LL FIND THAT YOUR FROND END WILL WASH AWAY IN CORNERS AND YOUR BACK END WON`T BE ABLE TO KEEP UP UNDER PRESSURE CONDITIONS. IT`S A LITTLE EXPENSIVE BUT IT WORKS BEST. ONE OTHER SETTING I`VE HEARD TELL OF IS, SET YOUR RACE SAG AND FROM THERE TURN THE NUT 360° LOOSE THEN LOCK IT, APPARENTLY IT WORKS, HAVN`T TRIED IT MYSELF YET. CHEERS.

karlp · Mar 5, 2003

CC-
I fitted '97 xr 400 springs in the forks. Yhey are quite a bit longer than stock. I did not use the stock spacer. With the fork leg fully extended, it seems to me I had to compress the spring about an inch, inch and a half to get the cap nut started.

I have not measured the fork oil level. Whatever its got from the factory.

Never, bought it new in September.

I can reset the race sag to 100. That seems like it is in line with what spike mentions.

By free sag, do you mean front or rear? Or both?

I don't mind revalving, but I'm hoping to exhaust all other possibilities first. The bike was almost unridable with the stock springs and is much better now, just a bit harsh.

canyncarvr · Mar 5, 2003

If you didn't reuse the stock spacer, then your preload isn't hugely out-of-whack (at least for that reason). That was the point of the question.

Doesn't sound like you measured the preload specifically? That's not according to hoyle, yanno?

Free sag question is in regard to the rear. That's how you determine if your shock spring rate is wrong. Too much free sag=too 'big' a spring, too little=too 'small' a spring.

If you're feeling 'every pebble' and your free sag (race, say, set to 100mm) is 2", you need a lighter weight spring.

One of the notable differences of the longer honda springs was I did NOT feel every pebble as I did with the other springs. ...and I'm using .40s. (yours are the .38 variety)

If your rear spring is the correct rate, I don't know from what you describe what would be causing the 'every pebble' mode.

karlp · Mar 5, 2003

I'll check the rear spring free sag and race sag. I'm quite happy with the improvement up front, most of what I'm complaining about seems to come from the butt end.
The stock fork oil does seem quite thick though....
My weight is right at 175 w/gear, maybe 180 counting mud.

Karl

karlp · Mar 24, 2003

Apologys to this forum. "Every stick and pebble " is not a very quantitative way to describe conditions.
I rode about 30 miles saturday. The first ten before making any suspension adjustments, the last twenty after setting things as shown below. I'll try to more accurately describe hoow it is acting in the first ten miles.

Approaching a tight left hand turn, about 75 Deg. corner, mid range in third. Speed is good for corner approach, off the seat about 2", clutch in throttle off, easy front brake pressure until the front end is into the corner, no rear brake. BACK END CHATTERING LIKE MAD. Back end settles down a bit as it gets into the turn. Off the brake, clutch out, down on the seat, on the gas. At the exit to the turn are a series of roots about 1.5 to 2" in diameter. BACK END GRABBING AND SKIPPING, TRYING TO DEFLECT LEFT AND RIGHT. About 75 feet ahead are two trees about 30" apart. On the gas to 25' from the trees, off the seat about 2", throttle off, on front and rear brakes, series of braking bumps ARE TRYING TO KNOCK MY FILLINGS LOOSE.

Approaching a tight right, bit more than 90 deg. Top of second gear. Off the throttle, clutch in, down onto the seat, skid the rear into the bottom of the corner. As the rear skids IT IS BOUNCING OVER THE TOPS OF THE ROOTS/BRAKING BUMPS. Get the rear skidded into the corner, clutch out throttle on, trying to pull back up to standing and the rear is exiting O.K. but a little harshly.

After about ten miles of this I headed back to the house to readjust to the following :
Rear race sag reset to 101 mm from 92, resulting in free sag of 47 mm
Clickers were set compression 8 from full hard, rebound 6 from full hard. Reset to what the manual says; 13 from hard on compression, 15 on rebound I think.
Front race sag 63.5 mm, resulting in free sag of 38 mm. I made no adjustments up front.
T his greatly improved the suspension performance. Do the free sag/race sag numbers look right? I'd like a little more plushness at higher speeds. How should I move the clickers?

Thanks in advance for any help. I'll try to stick to facts in the future.

Karl

canyncarvr · Mar 24, 2003

I'm no suspension gheru. I look at a stack of shims and wonder how anyone makes any sense of that stuff.

Still...the back end jacking you around sounds like too much compression or too little rebound?

Oops. I'd skipped your last 'changed to' stuff.

Judging from what the shock was set to (too far 'in' on both), your forks are maybe as goobered? Set 'em to around 5 in from full out. My bike's suspension improved considerably with 3 clicks. A big difference. 'Spearmint with it.

47mm free sag is a bit on the much side. You'd do better with a 4.8 spring (I'm assuming you have a 5.0). I can't say from experience what a .2kg/mm difference in shock spring makes. The 5.0 fits me perfectly.

You might consider a different pullrod set. The pieces from devol don't lower the bike much, but do improve the shock action a good bit. At $100 or so (with the required KX250 bolts) that's probably a bit more than a shock spring?

I don't see a fork preload figure. You don't need more'n a couple mm

karlp · Mar 24, 2003

I'll get the fork pre load shortly. I put '97 xr400 springs in there and used no spacers. Seems to me with the fork fully extended I had to push the cap nut down 1-1.5 inches. I'll check the fork clicker settings.
The 20 miles ridden after adjustment were much better. Can you describe conditions and effects of playing with the shock clickers? I'll do a search if you'd rather.
Thanks for your help. I was thinking this was one evil little sucker 'till I found out how boogered up I had it!

Karl P.

canyncarvr · Mar 24, 2003

re: shock clickers

I was looking for the wheel to do the best job of following the ground that I could make it do. With compression too stiff, the leading edge of an bump would make the bike kick up (kick my rear, too). Soften it til it doesn't do that.

With rebound too 'slow' on the trailing edge of the same impact, the rear wheel leaves the ground...make it faster such that it comes down 'in time', but doesn't kick your butt at the top of a bump.

I found a couple less clicks on compression to help on hills, too. The bike 'sags' more with resulting increased traction as opposed to 'levering' the bike over a too hard setting resulting in a loop-it.

Just a couple clicks less (from what I had determined to be good-to-go on the forks) worked wonders on places I was stuck on uphills, too. One particular time, I'd gone rooting around in the brush looking for a trail outlet. Ended up in the bottom of a draw, no way to go but back up. Had a hell of a time getting started from the bottom with the frontend right up against a rock/root. Everytime I'd start moving, the front end would come up on me..couldn't get going. Two clicks down on the forks allowed them to compress (give) enough to let the front end go over the obstacle as opposed to pushing the bike up.

Those things got settled a few years back when the bike was knew to me. Found only last week or so that the problems I'd been having with the frontend were largely clicker related. I couldn't pick and choose tracks too well on uphills..downhills would give me loads of 'tucking' problems...the bike didn't seem to want to track straight at all. Changing from 8 to 5 clicks made it a different animal.

Point is, never consider tweaking either fork or shock 'done'. As new situations/problems develop...you may be surprised what a finer tweak (than used before) will do for you.

Don't know how you'd get 25-35mm of preload with NO spacer. What was the spring length? Seems I've read your measured length someplace. The honda spring should be around 530 or so.

Have fun!

Plushness in suspension

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