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1998-2002 KX 250 Freshening up

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.

I just looked back. You are right. Yamaha didn't change the brake line till 2005. Last real update to the YZ 2 stroke line till recently. Kawasaki and Suzuki changed theirs in 2004.
 
So finally had some time to get back to working on the bike. Got the rear shock rebuilt and linkage lubed up. I'm going to reassemble tonight and hopefully ride some Monday.

Changed jobs during the break too. Im finally getting to be pretty much dirtbike only. Those sxs's were wearing on me hard. Totally different crowd.


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Went riding yesterday. Huge difference in the bike. Much better handling and balanced feel than before either end was done. It is a lot softer on the valving so it tracks much better than before and doesnt kick on roots and rocks.

The racetech valving is kinda generic compared to having someone valve your suspension to you specifically. It is still way better than just trying to make clicker adjustments if your trying to single track a motocross bike. It also allows you to do it at home instead of shipping your forks out somewhere. Which is really expensive these days.
 
So its been a bit since my last update. Ive changed jobs, but i have access to some sweet KTM parts now. Upgraded the stock master with one off a 250sx.





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Also replaced the front disk and pads.

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As well as adding a 18" rear wheel and a new sticky tire.

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Just a touch hack but got it true minus a small bump where its put together. Which is probably the cheap wheel. Will be fine for what im doing.
 
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As it sits now. Put the new front sticky/cheater on today. Rode it with the rear, but havent with the front yet. HUGE difference with just the 18"swap and new rear tire. Will have to ride with the front and report back. Still plan to do the trans swap, swap in a taller bar and taller seat.


Brakes are 1 finger with some progressive feel but still pull rear tire up. Also the sticky 18" rear is amazing. Not near as much arm pump from trying to ride the clutch to controI rear wheel spin amd the traction to crawl thru stuff without it. The low gear trans will make it almost trails bikeish. Which is kinda what im looking for.
 
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Did the 18" swap on my YZ as well. I love the feeling of the extra sidewall but it screws me when I pinch flat them. An 18" flat is a massive pain in the ass compared to a 19" flat.

What cheater tires are you running?
 
Did the 18" swap on my YZ as well. I love the feeling of the extra sidewall but it screws me when I pinch flat them. An 18" flat is a massive pain in the ass compared to a 19" flat.

What cheater tires are you running?
Shinko 525 on the rear and the mx216 "fat tire" on the front. Havent done any riding with the front yet.

The 19" that was on the rear was old. I put it on when i built the motor 7 or 8 years ago. So I'm going from it to a 18" sticky which is opposite ends of the spectrum. The 19 wouldnt hold a line for shit if you was side hilling or trying the ride the edge of a rut or even pick a specific line thrrough slate type rock that we have around here. It would also spin and cause a lot of kicking in the rear on square edge ruts, tree roots, and rocks. So I would try to control that with the clutch. Which of course caused a lot of arm pump and wore me out anyway.

The 18" would hold a line and didnt require constant clutch work to keep it from wanting to spin. So not near the arm pump and my back wasnt cramping from the pounding of the rear tire spinning and bouncing all over the place. I will say that they wouldnt be good for high speed or anything that has you up on the tank with it layed over. The knobs are too soft and the bike slides away from you.
 
Any particular model you rob them from?

This is the part number I used. There are some different piston sizes which will change brake feel depending on the size that is on your bike now. Off top of my head its from a 2010 or so 250sx, xc, xcw. I think its a 10mm piston. They went to a 9mm in '12 maybe. I havent worked with the ktm stuff that long to have it all in memory yet. I can look tomrw at work and tell you more specifically


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Interesting. I have a YZ125 front end on my KDX and apparently those years had an 11mm MC, which is probably fine on a motocross track but it's a little too on/off everywhere else.
 
Working on pulling the motor to swap the trans and a couple upgrades along the way. The first few upgrades.


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The setup on the left is the old one for my 450 Honda. Going to use the resi as a backup for the new ktm one. I just ordered a new braided line and replacement for the slave for a kx250. Its a 9.5mm master.
 
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So im going to try something a little different for the trans swap. The 4 bushings in the bag are for the shift fork shafts. Allows me to put the KDX 250 10mm shift forks in the KX 250 cases that have 12mm shafts. The 2 bigger bushing are to "I hope" allow me to use the KX 250 clutch basket on the KDX input shaft. I'm going to try that and see if it works. Going to get the motor out tonight maybe.
 
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Interesting. I have a YZ125 front end on my KDX and apparently those years had an 11mm MC, which is probably fine on a motocross track but it's a little too on/off everywhere else.
I looked this up for you and kinda forgot about it till i posted those pics. If I remember KTM disco'd/superceded the older brake masters to the newer part number which is a 10mm I think. I wrote all the part numbers down but Idk what i did with it now. I can get you the numbers if you want them thou.
 
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My last "upgrade" parts came in. So now i just got to get off my ass and get the motor apart. The black piece is a universal linkage skid plate im going to add to my aluminum chassis skid i already have. The prox basket is only one I could find in stock other than wiseco. The prox is billet made by Hinson supposedly. The other one is forged and machined. So I went with the billet one.

The rings and bearing are not an upgrade, just replacing them while its apart. The sproket is same 13t im running now. The older counter shaft has a different spline count.


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I don't know for sure the amount of time on the motor because I don't have an hour meter. I'm going to guess andsay maybe 30hrs if that much since I put new cylinder, piston, crank, and all the bearings. Kawasaki plating was shit back then thou so doesn't really surprise me. I'm gonna rering it and run it till it blows though. Trans pics coming up..
 
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Top shaft is kx with kdx on bottom. The only way I have seen it done previously is to sleeve the kdx shaft up to size of the kx. I'm trying different route. That piece on the kdx shaft is a bushing out of a Honda trans. It happens to fit the kdx shaft on the inside and has a slight interference fit on the sleeve that the clutch bearing ride on.

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As in the pic above. The only issue is the bearing in the center case that this shaft rides in. It also made for the larger shaft of course. I'm guessing that's why the smaller shaft is usually sleeved up in size.

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I'm going out on a limb and try using this stuff to "glue" one of the bushings to the shaft. So the bearing will spin instead of the bushing spinning on the shaft.
 
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"Glued" the bushing on the input shaft and it seems to be holding fine. We will see after I get it together.

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Got the trans all assembled. I was able to find all 5 gears and neutral. As long as it works after the motor is all the way together.

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The bushings inside the clutch sleeve to make it fit smaller input shaft.

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Flywheel weight reinstalled. It obviously sat a couple of those years in storage with some moisture under the ignition cover.

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And the new clutch basket installed. I didn't have a press at home. Tried a couple different ways to get the gear out before breaking the center of the stock basket out. That made it fairly easy.

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Bike is back together. Went for a short trail ride today. Easy stuff because the wife was riding with me. So no hard climbs or tight single track yet. Clutch engagement is so much more smooth. Should make it a lot more fun to do some challenging stuff. I will probably try to get some in after work this week.

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Bike has been running fine. It's so much more fun doing tight, slow speed stuff now. Clutch engagement is much easier to control without having to constantly adjust the cable or the plates hanging up on the groves in the stock basket. Do have one little issue free play in the slave. I have about 2mm too much according to magura. To tighten that up you have to space out the slave.

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In that pic you can see there is no more room for the slave to move out. Its actually riding against the cover as is. The boyesen cover sticks out more than the stock plastic cover. That spacer makes it worse. So I did some grinding on both and made some room.

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Now there is room for the slave and any adjustments needed.
 
That's pretty much everything I had planned to do. I would like to replace the seat foam and cover with some taller foam. I'm pretty much done putting upgrade money into this thing. Its 23 model years old now with some 33 year old motor parts inside of it. It's pretty much as good as it will ever be for what I am trying to do. You can't upgrade your way out of the wrong steering head angle or chassis setup.

This was brought in on a consignment sale. So I could always take the, still wrong bike, and go the brute force route. It is really clean and unmolested. My wife said buy it because it's cheaper than a new bike. I said I'd love too but I would still need a new bike. She wasn't as ok with it after that.

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It's pretty much as good as it will ever be for what I am trying to do. You can't upgrade your way out of the wrong steering head angle or chassis setup.
True true. I like the YZ I built a lot, but I definitely feel that it's a dated machine when I hop back on it off of my 450. Still a barrel of fun though, old jap smokers just have such a charm.
This was brought in on a consignment sale. So I could always take the, still wrong bike, and go the brute force route.
I've done a not insignificant amount of hard enduroish rock hopping on a KX500. The tractor torque is sort of useful but they are big heavy pigs, the geometry will make you wish for your 250 back, and it's more of a process to start when you stall it.
There is also not a product on the market that can tame the clutch on a KX500. And that's if there's any feeling left in them to pull the lever in the first place! :dustin:
 
True true. I like the YZ I built a lot, but I definitely feel that it's a dated machine when I hop back on it off of my 450. Still a barrel of fun though, old jap smokers just have such a charm.

I've done a not insignificant amount of hard enduroish rock hopping on a KX500. The tractor torque is sort of useful but they are big heavy pigs, the geometry will make you wish for your 250 back, and it's more of a process to start when you stall it.
There is also not a product on the market that can tame the clutch on a KX500. And that's if there's any feeling left in them to pull the lever in the first place! :dustin:

Ground clearance is probably 2 inches or more less than a newer enduro bike. Plus the lazy steering angle makes this thing turn like a lwb truck when doing tight technical 1st gear stuff. So i have got to get something newer. I will hang on to it thou. I could still revalve it and do laps on a track pretty easy.


Oh the clutch on that kx would give Popeye arm pump using all 4 fingers. I do not care to try and trail ride that 500. That 250 is kicking my ass trying to drag it over rocks and thru peg deep ruts. I'd love to have it to motard it and ride it to work. I want that extra ground clearance, 20 lb weight savings, and slow speed turning of a new TM or KTM over that 500 grunt.
 
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