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1998-2002 KX 250 Freshening up

slowlygettingthere

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This bike came into the shop with a bad crank 6 or 7 years ago. It still had the original tires and exhaust on it. I figured it had sat in someone's garage not ridden for most of its life. So I bought it and went through the motor. New kawi cylinder, crank , transmission bearings, and a couple parts of the PV that showed a little wear. I put a few hours on it and it has pretty much sat for the last 3 years. Going to strip it down and freshen up all the bearing and send the suspension off to be revalved and sprung for my weight. I have a kdx trans I would like to use. So I am going to split the cases again to swap the trans out or build another motor. I have the other cylinder I could make a big bore out of. Couple different ways I could go with on the motor. Going to get the chassis sorted first. Im also going to do a plastic update kit to make it look a little newer. Anyway the way it currently looks.

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Its not too complicated. You use the kdx trans and shift forks. Have to make bushings for forks and the input shaft will need to ne sleeved up in size a little. Other than than its a swap out. I'm going to post pics when I do it. I want something I can ride on a little more technical trails. So that lower first gear is what I am after.


Seeing that pic reminded me of just how much I hated those graphics when I bought that bike. I just made sure it ran good. wasn't worried so much about the looks. This is the update kit I'm going with.



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Seeing that pic reminded me of just how much I hated those graphics when I bought that bike. I just made sure it ran good. wasn't worried so much about the looks. This is the update kit I'm going with.
Yeah the whole green/black flames thing didn't age well. My KDX has a seat cover that would go right along with it.
 
The difference in stock trans ratios in the 91-94 KDX vs 98 KX250 vs 99-01 KX250



91-94 KDX 250 /// 98 KX 250 /// 99-01 KX 250

1'st - 2.385 - 2.133 - 1.800

2'nd - 1.767 - 1.625 - 1.625

3'rd - 1.388 - 1.333 - 1.333

4'th - 1.100 - 1.136 - 1.136

5'th - .929 - 1.000 - 1.000



....

I want the lower first gear is what I am shooting for. I'm not in 5th very much but the over drive would be nice if you could use it.
 
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Too bad you can’t just swap the gears instead of having to do the whole trans
 
Nice, I had a KX125 I was going to kdx swap but it ran too damn good and a buddy ended up buying haha.

I had modded it to run a newer 4 stroke IMS tank and plastics (before you could get that restyle kit)

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Would be, but 1st on the input shaft is pressed/made on it. I mean I guess you could possibly get it off without fubaring it, but I doubt it. You could get by without making the input shaft bushing if you used the KDX clutch I think. I only have the tranny so I don't want to hunt a good KDX basket down and buy a new clutch for it.
 
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New parts coming in. A couple of these I already had but most I ordered. A 45 pilot was stock but mine ran a little fat on bottom before. I'm putting a 42 in it to start. Intake boot was pretty beat too so i'm replacing just in case. Also have a vforce reed setup that will go in this time. Those part numbers should work for 00-02 models. Probably work for the 98 and 99 as well.
 
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Nice, I had a KX125 I was going to kdx swap but it ran too damn good and a buddy ended up buying haha.

I had modded it to run a newer 4 stroke IMS tank and plastics (before you could get that restyle kit)

Not too bad. I wouldnt mind riding a 125 but haven't been that small in 20+ years. Even then I was too heavy really. Im really too heavy for a 250 but the price of good 500's are so high i would buy a new Beta 300rr before buying a 500.

I will need a tank eventually. One if the molded in nuts spins in the tank. Idk if I will go ims or try to hunt a good tank.
 
I ran across another set of shrouds and number plates I had. I removed the decals off the rear fender and used my other set of plastic I had for now.I haven't been able to find my vforce setup yet. Its back together to and I plan to fire it off this weekend.

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Gold Valves made it in today. Gonna break the forks down next week some time. May ride it in between doing forks and the shock.
 
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I got the forks apart. Going to clean them at work today and reassemble them tonight maybe.

Someone has been into the forks before. Springs have been changed. I haven't looked at the valving see if it has been messed with or not. The way it rode I would say that part was still stock, but it did have stickers on them.
 
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I try to avoid bike forums because it never fails that I get temping to buy a bike. Curse you for bringing this here!!

But really, I love this and seeing what you are doing to freshen up an older bike.
 
I try to avoid bike forums because it never fails that I get temping to buy a bike. Curse you for bringing this here!!

But really, I love this and seeing what you are doing to freshen up an older bike.
Ya its tough. Try working at a dealership.


Thanks. I want a new TM or maybe a Beta, but I'm so out of shape. I can't see spending 10 or 11k on a new one yet. I can put 1 or 2k into this one and ride myself back into shape. Then I can reward myself with a new one. That's my reasoning anyway. Honestly with some upgrades this bike won't be all that bad. I hope to get the fork rebuild pics up tonight or tomorrow.
 
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These are only on the compression side. The gold valves with new valving is the only mod I am doing other than disabling the bladders. The springs have already been changed but I have no idea the what rate they are. They seem stiffer than stock though. So I will see how it feels after I get it back together.
 
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Make any changes to the shim stacks to compliment the gold valves? What's the goal?


Yes I used racetech's recommended valving. You give them your weight, riding type, and "class" or speed. Then gold valves comes with a bunch of valving shims. They give you valving specs and you build the shims stack based on that.. None of the stock valving is used.


2000 was first year for bladder forks on kx's. They were not really plush, were really harsh in the mid stroke and still bottomed fairly easy back when the thing was new. I'm heavier than what the stock valving was designed for by a good bit. Even with that the forks felt like shit when riding enduro type stuff. Way to harsh in the first half of the stroke. So I am trying to improve that as much as possible.



"Gold Valves® are Race Tech's Custom Valving Kits. They are designed to break through the limitations of stock piston designs. Research has shown that the stock piston ports induce unnecessary harshness. Gold Valves are designed to reduce piston restriction so harshness is dramatically reduced. This allows the valving stack to be personally tailored to the individual rider. Tests have proven that bottoming resistance is actually increased as the harshness is decreased. Traction is also improved.

The key is a careful combination of the Gold Valve itself and the valving stack. Custom setups are computer calculated with the Digital Valving Search (DVS) on our website. Developed and refined for over 18 years, this computerized system calculates the proper setup for the individual rider including spring rates and clicker settings from over 300,000 possible combinations."



I know that is sales hype but their description.
 
Worked on the clamps a little. No performance gain. Just had some time at work. The top clamp has a coating that is a p.i.t.a. to get off. I just cleaned the casting marks up and smoothed them a bit with a buffing pad.


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Got the front back on finally. Changed to CR style brake line routing. Honda had a patent on how the front brake line that ran out in 03 I think. I used 04-06 rm250 fork guards with a braided line. You will have to swap the m6x12 for m6x20 with a small spacer to make the holes line up, but otherwise a bolt on. Brake line is about 8 inches shorter. Should help with braking performance. If that doesn't help enough I will swap to a Honda master cylinder.




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I like the looks of the bigger guards more than the smaller stock ones. The works (Kawasaki) bikes of course had billet lowers so the ran a Honda style fork guard in 01. Some of the 2000 (works KX's )bikes ran a stock style line. I don't know exactly when they started running the shorter line on the works bikes. I think all Japanese manufactures swapped to the short line in 04.
 
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I don't know exactly when they started running the shorter line on the works bikes. I think all Japanese manufactures swapped to the short line in 04.
I know that when I bought my 04 YZ250 a few months ago, the stock line routing was long line style. Yamaha probably just saved that particular update for the big unveil of the aluminum frame in 05 though. None of the other makes had that in store at the time.
 
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