Officially tired of nose dive...

[Apex]

So I am thinking about upgrading the front suspension on the bike.

Who has used Race Tech springs? I have calculated rates from their site based on weight. I even went down 10lbs in weight to verify that just in case I start to lose weight (that is the goal in a few months), that the same rates will still apply. I am glad to say they do. They rated me at .70kg/mm.

FRSP S2938070 RT FRK SPR 29.0x377mm .70kg $109.99

I don't want stock rates (0.440 kg/mm ), but the more performance rates. 0.70kg is a huge increase, but I want to see what others have to say before I lay down some cash for springs.

Any info would be appreciated!

[Snake]

Have you tried going with a heavier weight fork oil? It may control the nose dive. It's worth a try before changing the springs. Your fork oil may be due for a change anyway.

[Zim]

Sonic Springs sells the same rate springs for $30 less. You can also look at experimenting with different oils and/or valve emulators, either Race Tech's or Ricor's.
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[Apex]

Just for your information, when I brake, I brake.

Most of the time I take it easy on the brakes. But if I get into "racer mode" on a backroad, I'm like a guy at a track day (safer lean angles and not as steep on the brakes).

I do plan on doing a track day. I just don't really care for the lazyboy feeling that the front end gives. I honestly don't think that just fork oil and emulators can fix the problem.

It may be worth a try though. I have heard good things about emulators, so it may be worth getting anyway.

[bdavison]

Yeah, springs will help certainly.....but I agree with Snake....heavier fork oil is cheaper, easier, and works. Toss in some 15 weight fork oil and set the level at 200mm below the top of the fork, it will be a whole other bike.

Just take it easy till you get used to the different feel of it. If its too hard, back it off to 215mm. Stock level is between 225-205.

Ive even heard of people running them at 130mm, but that seems aweful hard to me.

[sombo]

Another idea that is on the 250.org site is to use the EX500 front springs. I think they are rated at like .550 or something around there. Those plus the heavier oil would make a major change I would think.

[greg737]

Don't let people talk you into a partial solution, an "on the cheap" solution, or some sort of strangely compromised solution to the EX-250's suspension.

The reason I say this is because the EX-250's suspension is the bike's weak point. It's not even an accident that the EX-250's suspension is sub-par. Kawasaki had to bring the EX-250 to market at a price point that would attract enough buyers to make good sales numbers because most people buy motorcycles based on CCs and HPs per dollar spent. If Kawasaki put the same quality items on the EX-250 that it puts on it's 600s, the EX would cost almost exactly what the 600 costs, and nobody would buy the EX because it would "seem" like a bad deal when viewed from the CC and HP per dollar perspective.

So Kawasaki had to cut corners somewhere, and one of the choices they made was to use old, cheap, suspension technology that was already in their production parts bin from previous production model years. By upgrading the suspension you're just correcting a "designed-in" deficiency.

I know that going from .44 kg/mm to .70 kg/mm seems like a big jump, but my experience with this exact change took my bike from "floppy, wallowing, limp-noodle" handling to "firm, confident, responsive"

I'm 175 pounds. I went with .70 Sonic Springs,

[DEXSPEED]

can anyone post a DIY on fork spring replacement on new gens too!?

[Snake]

Originally Posted by DEXSPEED

can anyone post a DIY on fork spring replacement on new gens too!?

The search button is awesome. See if this thread is what you are looking for.

http://www.ninjette.org/forums/showt...3200&highlight

[null0]

195 lbs and I went with .80 kg/mm Racetech springs and gold valves. Definitely got rid of the front end tuck under braking. They're a bit stiff for everyday riding, I definitely feel a lot more of the road at lower speeds.

[Apex]

Originally Posted by greg737

Kawasaki had to bring the EX-250 to market at a price point that would attract enough buyers to make good sales numbers because most people buy motorcycles based on CCs and HPs per dollar spent.

It is a wonder that Harley can sell any bikes.


So I need to get some springs, emulators and heated hand grips. Then I'll be good to go.

[kkim]

Originally Posted by Apex

So I need to get some springs, emulators and heated hand grips. Then I'll be good to go.

...in the mean time, preload the front springs with some washers the same diameter as the ID of the forks. It will up your spring rate for mere pennies. preload each fork leg with a washer stack of about 1/2" and see from there which way you need to go to get it where you want it.

[Apex]

I'm not sure I want to preload the front. The bad thing is if I were to run out of travel. The second that happens, it will jar the front of the bike. If I am in a turn and that happens, then I will be on the pavement sliding my way to home plate. It just worries me because I know when I get on the brakes, the front end dives to the point I know there is not much travel left.

I think I would just feel more comfortable swapping the springs. Thanks for the suggestion though!

[kkim]

you won't run out of travel if you stay sensible with the amount of preload. 1/2" is not that much, but will make a big difference in the stock spring rate.

do what is most comfortable for you. I just thought you might want to save the $100 you'll be spending on stiffer springs which in the end might make the front end too stiff (harsh) and lead to other front suspension related problems.

[Apex]

I appreciate the help!

I wish we just got good suspension from the factory.

[kkim]

IMHO, they got the suspension pretty close for the intended target market.

If you're a bit heavier/larger than "average", yeah, it could use some work. If you're going to be racing the bike, then again... yeah, it could use some work.

They did put some pedestrian parts on the bike, but they work surprisingly well for being so old in technology. If the suspension is a problem for you, by all means, fix it. But in doing so, you'll be putting in a lot of time/effort/money to get it "perfect", which you will never achieve.

What the bike lacks is adjustability. With the washer trick, you raise the spring rate by the number of washers you install. Too stiff, take one out... not stiff enough, add another washer. In that way, you can tune the spring rate for your riding weight and style.

With buying a higher rate spring, you're screwed if it turns out to be too stiff. To get a lower rate, you would need to cut the spring and add spacers. And if it were not stiff enough, you would resort to adding spacers to increase the rate, unless you bought a new set of springs.

To be clear, I've not done this w/ the ninja as I happen to like the suspension as is, but I have been playing with the same type of forks in the dirt bikes. Suspension theory basics are the same no matter what vehicle you're discussing.

Good luck fixing the "dive"... I have ridden a pre gen and agree that the suspension a bit softer than the new gens.

[Thrak]

Originally Posted by kkim

you won't run out of travel if you stay sensible with the amount of preload. 1/2" is not that much, but will make a big difference in the stock spring rate.

adding washers wont change the spring rate at all.. they'll still be .44 springs.

[kkim]

Originally Posted by Thrak

adding washers wont change the spring rate at all.. they'll still be .44 springs.

yes, but it's the spring preload you are changing.

[Thrak]

Originally Posted by kkim

yes, but it's the spring preload you are changing.

preload has nothing to do with spring rates (unless using progressive rate springs which arent all that common for motorcycles)... preload affects rider and free sag and ride height...

[kkim]

have you ever added spacers to a fork? I've done it and the front forks became more resistant to bottoming. care to explain what happened there?

[Thrak]

Originally Posted by kkim

have you ever added spacers to a fork? I've done it and the front forks became more resistant to bottoming. care to explain what happened there?

I'd be willing to bet I have alot more experience with motorcycle suspensions than you do... I'm not going to get into a pissing match with you but you say some pretty incorrect things around here and I hate seeing bad information...

Every spring has a max and min length, you can only compress a spring so far before you're at max compression. If you preload the spring you are taking away its available travel.You are not increasing the spring rate. You're reaching max compression sooner. If you add enough spacers the spring wont compress at all and you wont be any where near "bottoming" the fork out, it just wont move.

The problem with not having adjustable preload on these bikes is that it makes it more difficult to get proper sag settings. A properly sprung bike will be in the correct range for rider sag and free sag with minimal preload on the springs. Sag is an essential part of bike setup.

[kkim]

No pissing match intended. I'm willing to learn if you have something to teach.

I'm passing on what I've learned on suspension tuning by learning from others and experience.

Adding 1/2" of preload will not lead to the front spring coil binding (at least I've never experienced it).

When you set sag of a rear shock by adjusting the spring collars, aren't you effectively adjusting the preload by shortening/compressing the spring? Isn't that the equivalent as adding washers to the forks?

[Thrak]

You are adjusting the preload and yes its effectively the same as washers in the fork, but you're not changing the spring rate. The spring rate is fixed and determined when its made.

If the spring rate was variable they wouldnt sell .70, .75, .80, .85 etc... they'd sell .70 then say add 25 washers to get to .85 (or whatever).

[sharky nrk]

That is a true statement, what Kelly is suggesting is to adjust the preload via washers-which is a cheap, useful, and effective change. It may be all that is needed for some, while for others nothing short of a respring will allow for proper motion control. Thrak is correct, a spring has its properties set when manufactured, among those are free length, compressed length, rate, gradient, and geometry. All of these things are designed into a spring for specific purposes.

[greg737]

For the purpose of not continuing to muddy the waters on EX-250 suspension, this thread needs a "reset." Suspension oriented threads almost always devolve into an opinion-fest, often with some suspension-urban-legend and suspension-black-magic thrown in for good measure.

I won't even suggest what I think is the correct solution for a 175 pound rider of a pre-gen EX-250 (cough, cough.... .70 springs, 15 weight oil, emulators, and a good aftermarket shock) because all the infinitely more knowledgeable forum members will drop on me like a ton of bricks. And mentioning such a solution would also trigger the "penny-pinchers" who'll spend whole pages writing cost analyses highlighting the ratio of the bike's original cost to the combined total cost of the suspension upgrade.

[2WheelGuy]

Originally Posted by greg737

I won't even suggest what I think is the correct solution for a 175 pound rider of a pre-gen EX-250 (cough, cough.... .70 springs, 15 weight oil, emulators, and a good aftermarket shock)

^^^^That just happens to be the formula I am using as a starting point on my new-gen EX-250 (stolen from my pre-gen, they are pretty much the same). I'm testing it at the track this Sunday. I also weigh 175 w. no gear.

[kkim]

http://www.ninjette.org/forums/showthread.php?t=29141

[saber63]

my suggestion....

send the forks off to the best suspension company you can find withen a reasonable area (so your side of the country etc...) call um and see if they will do a set of 250 forks.

what they will do is weld the damping rods, and redrill them for a MUCH better damping curve, they can also add new springs for your weight/riding, or modfy the stock springs (preload etc..) if your only a few pounds off etc... should cost $200-$400... and its worth every single penny!!!

much better then anything you can do yourself. because a proper shop will put the forks in the fork dyno, and make sure they are as good as can be for you! (well if the shop is good that is ) it honestly made the suspension just about on par with the OEM stuff on my 03 CBR600RR....

two things... you will then want todo the same thing to our rear shock, as youll notice how poor it is (while getting on the gas at the apex) and it may make you want to upgrade any of your other bikes suspension


no matter what you do, good luck! and hope your happy with it!

-levi