I'll try it just resprung and see what it feels like.

 

If you ride rough terrain, don't be surprised if you get even more deflection off of hard edges. By adding stiffer springs, you are increasing the tendency to resist hard compression spikes....which means the hard hits are even harder. If you are in turns that have hard edges in it, you'll definitely lose some ability to hold a line in the turn, as the stiffer springs combined with the poor compression spike damping will decrease the relative time your front wheel is tracking on the ground.

Then again, if you aren't hitting hard bumps, it might not matter much.

If you really want to assess the difference, go to a place you can do a figure-8, and can do it all in say, 2nd gear. Go around and around it, until you find out how fast you can do it with your stock setup. Count the time for at least5 laps, the more laps you do, the easier it is to notice a time difference. Then, make the change, go back out and see if you are faster or slower. The more bumpy the turns, the slower you are going to be with the stiffer springs....that's because you are drifting wide with stock valves and stiffer springs...the front wheel just won't be biting as well as it skitters even worse with stiffer springs.

I've examined the stock piston bits in my hand...they are crude and severely limiting in adequate fluid flow. The improvement is obvious when you ride a properly valved front end. While stiffer springs are part of the corrective formula for most "normal-sized" riders, better valving is the most important bit when riding on bumpy terrain.

 

This whole issue brings up an interesting discussion/debate. I'll differ and agree with some of what FD and B58 are saying. Staying with the KLX fork only, the soft front springs do contribute to the compression spike. Since the OEM compression piston doesn't flow an optimum level of oil, the soft springs allow faster compression of the fork, thus aggravating the poor oil flow, resulting in a harsher compression spike. The heavier/appropriate springs will keep the compression speeds down a bit, thus resulting in the poorly designed compression piston to not play a bigger part in producing a compression spike which is basically a hydraulic lock.

Another factor is that the inevitable compression spike with the poor OEM compression piston will be worse when the soft OEM springs allow the bike to be lower in the fork travel when the compression spike occurs. If the bike is lower in its travel with soft springs, the head angle is steeper. The spike will upset the bike more noticeably when the head angle is steep. With the heavier springs, the bike is sitting up higher in its travel and that produces a slacker head angle. Then when you get a compression spike, the bike is more stable and not upset quite as easily.

The heavier springs will be an improvement IMO, but still a bit of a bandaid. Still, a bandaid is better than an open wound.

 

I have a bit before he ships the springs because of the fact they're special order items. I'll consider spending a little more and getting the valving parts.

 

$185 for the forks and $185 for the shock. Yeah, I'll wait to see if I really need it.

 

You guys are something. You got me looking. Racetech says they have no rear spring for my bike. Moto pro does.

Feral Donkey, that would be $185 plus parts and shipping.

A fork valve kit is $159.00 I will gladly install it my self. Rear spring is another $120.

Kamasacki put stiffer springs in the front when they made it an SF, so I don't need those.

Thinking......

David

And yes, I need the valve kit for the front. The faster I ride the bike, the harsher the bumps are. It beats me up.

 

I assume the sag will be set correctly with stiffer springs, so, unless you are in an increased G-force situation, the head geometry is the same on either set of springs prior to the hard hit, so, the jolt and associated deflection/skittering will be worse with the stiffer springs.

Again, the best way to know for certain is to time-trial test it on a known course.

 

With stiffer springs are more noticeable impact, certainly, but placing the regulator compression at the point will get softer fork absorption very similar to original, hard springs.
I checked.
The problem comes because we ran out of clicks of regulation, we must place it in softer steady.

 

Yeah, I get where you're coming from about sag, but sag is with the bike sitting still. When you're riding and hitting successive bumps and even under braking the front will sink deeper in its travel. The worst case will be under braking when the overly soft springs are going to let the front end dive regardless of sag setting. The head angle will be steeper. You're right about the increased G-force situation...whoops, V-dips, braking, etc...but that happens a lot when riding a dirt bike, doesn't it?

 

Where I ride, in the desert, stock front ends with stiffer the springs drift wide in turns. The rougher the terrain, the more they drift wide, unless they are fitted with quick-reacting valving. I've done testing on four different bikes (DR350, KLR650, XR650L, KLX250), and they all exhibit similar handling problems if stiffer springs are added to stock valving or damper rods, as the case may be.

My front and rear aftermarket-improved KLR650 would whip the XR650 in a figure-8 time trial test, even when the XR had the same rear-shock improvement paired with stiffer front springs, using the stock front valving. The XR picked up some time when I went back to stock front springs (which are known to be too soft for my weight), because the softer springs would allow the tire to bite better. But, the XR couldn't beat the improved KLR until the XR had it's front valving speed increased. Same with the DR...it had to have faster valving to beat the KLR. Same with the KLX....I tried it stock to see what the figure-8 time would be in stock form, just because I had the data from the other bikes.

Still, the KLX's main problem is lack of oil flow on sharp hits. The bike bounces all over the trail until that is fixed. THEN, the stiffer springs are a benefit...actually, stiffer springs are a necessity for someone of my weight.

To be accurate I never did time-trial test the KLX with stock springs vs stiff springs with stock valving. The inability to hold a turn was so familiar, just like the other three bikes, I went straight to better valving and stiffer springs.

Once again, a timed course is the true measure of the benefit, or lack of benefit, of any change.

EDIT: Actually, timed course while monitoring Heart Rate is more accurate. The faster the time at a given heart rate, the better the bike is performing. HR is a proxy for effort expended. The better the bike handles, the less effort is exerted, even if the time isn't improved. When both lap time and HR drop simultaneously, THAT is the ultimate goal.