1990 kx250 O”show replica ...completed

sandman768
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sandman768 9/27/2019 4:12am
9/27/2019 4:12am
mxsixty wrote:
Sandman your builds are awesome! I call in weekly to check in on what you are up to. Love the RM125 any updates? But yeah when...
Sandman your builds are awesome! I call in weekly to check in on what you are up to.
Love the RM125 any updates?
But yeah when I did my 1990 KX250 there was little in the way of pics or information on the net (trust me I looked high and low) on how to run the wiring harness and cable's but nothing was out there I have a manual also but nothing is clear.
Your pics of your 1990 KX250 are the 1st pics I've seen of how it came from the factory!
If you could post a few pics of how the wiring harness and cable's are run from factory it would be awesome for future reference for anyone doing a 1990 KX250 and for me to correct mine.
As you can see from this pic of my 1990 KX250 just how wrong I got it! with nothing out there to go by.
Cheers and keep up the great work you do awesome builds of classic mx bikes!.. .


Your bike looks great! The RM125 sits in the garage, I decided it is best to leave the RM as a garage queen due to poor parts availability. I should at least run it up & down the road a few times!
I tak a lot of photos during the teardown process so I can reference them later, I”m annal about wiring & cable routing!
I will take more for you & post them. The wiring for this bike under the tank looks a little sloppy, but with the tank taking up a lot of the available space it may be original. The tank was remove at some point by the P.O. To repair a spinning shroud nut insert, not sure if they messed with wiring routing.
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riv187
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riv187 9/27/2019 4:44am
9/27/2019 4:44am
I had a 1990 KX250 back then. It was like a 125 on steroids. When I first got it,,the thing fouled plugs left right,,even B7. I found the solution from Carb Wharehouse.- a 5 (or 5.5) slide. Cleaned up the low speed richness. The parameter frame was known for cracking somewhere near gas tank on side. Beautiful build.
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sandman768
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sandman768 9/27/2019 5:39am
9/27/2019 5:39am
riv187 wrote:
I had a 1990 KX250 back then. It was like a 125 on steroids. When I first got it,,the thing fouled plugs left right,,even B7. I...
I had a 1990 KX250 back then. It was like a 125 on steroids. When I first got it,,the thing fouled plugs left right,,even B7. I found the solution from Carb Wharehouse.- a 5 (or 5.5) slide. Cleaned up the low speed richness. The parameter frame was known for cracking somewhere near gas tank on side. Beautiful build.
Good info riv187.... I don’t remember fowling plugs on my 90, but I rode mostly sand and did not spend too much time in the lower rpm range. I do have the MXA test of the 90 and they mention the low end jetting needing clean up, but they did not offer any specs...I did not understand jetting very well back then and ran whatever jets came in my bikes! I never kept my bikes for more than 1 season back then, so I did not experience any frame breakage on my KX”s. I do remember a few fast A riders cracking The aluminum upper shock mounts. The mounts would flex with the frame and crack. When I tried to remove the upper shock bolt, it would not come out, I had to loosen all 4 of the aluminum mount bolts to take the tension off the shock. Funny how the more things change....the slide change is exactly what my 18 KTM 250 SX needed to clean up the low end!
mxsixty
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mxsixty 9/27/2019 5:55am
9/27/2019 5:55am
mxsixty wrote:
Sandman your builds are awesome! I call in weekly to check in on what you are up to. Love the RM125 any updates? But yeah when...
Sandman your builds are awesome! I call in weekly to check in on what you are up to.
Love the RM125 any updates?
But yeah when I did my 1990 KX250 there was little in the way of pics or information on the net (trust me I looked high and low) on how to run the wiring harness and cable's but nothing was out there I have a manual also but nothing is clear.
Your pics of your 1990 KX250 are the 1st pics I've seen of how it came from the factory!
If you could post a few pics of how the wiring harness and cable's are run from factory it would be awesome for future reference for anyone doing a 1990 KX250 and for me to correct mine.
As you can see from this pic of my 1990 KX250 just how wrong I got it! with nothing out there to go by.
Cheers and keep up the great work you do awesome builds of classic mx bikes!.. .


sandman768 wrote:
Your bike looks great! The RM125 sits in the garage, I decided it is best to leave the RM as a garage queen due to poor...
Your bike looks great! The RM125 sits in the garage, I decided it is best to leave the RM as a garage queen due to poor parts availability. I should at least run it up & down the road a few times!
I tak a lot of photos during the teardown process so I can reference them later, I”m annal about wiring & cable routing!
I will take more for you & post them. The wiring for this bike under the tank looks a little sloppy, but with the tank taking up a lot of the available space it may be original. The tank was remove at some point by the P.O. To repair a spinning shroud nut insert, not sure if they messed with wiring routing.
Thanks Sandman that would be great if you could put up a few more pics of the wiring and cable routing.
From memory with little to no room under the tank I just bunched up the wiring and jammed it in between the radiators and it looks like I got the clutch cable all wrong going on your pics lol..
Man I wish my bike had as little hrs on it as yours mine was mostly in boxers when it got it!.

Good to hear you are looking after the RM125 you just don't see em anymore they might not have been the fastest but damb such a good looking bike with the all blue frame/engine combo IMHO.

Looking forward to updates on your 1990 KX250 probably the lowest hr 1990 still out there!
Cheers...

The Shop

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riv187
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riv187 9/27/2019 6:01am
9/27/2019 6:01am
The slide change for me was taboo back then, but pilot and needle height was missing the mark. $50-80 was cost I remember when I called CW. I choked ! I asked a old timer at local shop about it,,and he told me to get out my file and do it systematically. I cheated and used a Dremel. After 3-4 .020" cuts, and test hits through back yard,, response was sharp and a different bike. I'd reached the point of no more improvement and stopped. 25 years later I got a 2017 Husky TC250....and history repeated. Get out the dremel and start carving..For me the 87 KX250 I rode before the 90 worked better,,more low end for trails and the hard pack tracks I did,,the 90 even jetted nice was a handful on the slippery dusty tracks. It was pretty though and in sand would've been a blast! I like your work, and it's cool to see a uncommon bike saved!
mxsixty
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mxsixty 9/27/2019 6:25am
9/27/2019 6:25am Edited Date/Time 9/27/2019 6:45am
riv187 wrote:
I had a 1990 KX250 back then. It was like a 125 on steroids. When I first got it,,the thing fouled plugs left right,,even B7. I...
I had a 1990 KX250 back then. It was like a 125 on steroids. When I first got it,,the thing fouled plugs left right,,even B7. I found the solution from Carb Wharehouse.- a 5 (or 5.5) slide. Cleaned up the low speed richness. The parameter frame was known for cracking somewhere near gas tank on side. Beautiful build.
When I did mine I did research on jetting and tried finding different sides for getting the jetting right on but couldn't find anything as far as different slides or needles, parts seem to have dried up for these older bikes or I weren't looking in the right place?.
But in the end with jets I seem to have got the jetting ok for my ridding I'm no pro or anything I just ride for fun (at 46 yeah I'm getting old ish lol)..
I like the on off power! not really a putt around bike I did foul one plug from putting about not cleaning it out on the pipe, since then I've dropped the needle gone one clip up on the needle seems right on now for here and my sea level.
I forget what main and pilot jets I ended up with but yeah this engine is at it's happiest revving..
https://youtu.be/b-simEd4JX4
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sandman768
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sandman768 9/27/2019 6:30am
9/27/2019 6:30am
mxsixty wrote:
When I did mine I did research on jetting and tried finding different sides for getting the jetting right on but couldn't find anything as far...
When I did mine I did research on jetting and tried finding different sides for getting the jetting right on but couldn't find anything as far as different slides or needles, parts seem to have dried up for these older bikes or I weren't looking in the right place?.
But in the end with jets I seem to have got the jetting ok for my ridding I'm no pro or anything I just ride for fun (at 46 yeah I'm getting old ish lol)..
I like the on off power! not really a putt around bike I did foul one plug from putting about not cleaning it out on the pipe, since then I've dropped the needle gone one clip up on the needle seems right on now for here and my sea level.
I forget what main and pilot jets I ended up with but yeah this engine is at it's happiest revving..
https://youtu.be/b-simEd4JX4
Excellent video! Sounds great...
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sandman768
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sandman768 9/28/2019 8:55am
9/28/2019 8:55am
Stock jetting: Pro Circuit
Main. 160. 160
Pilot. 60. 58
Needle N85C 3rd clip N85C 2nd clip
Slide #7 #7
A/S. 1.5. 1.5
sandman768
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sandman768 9/28/2019 8:59am
9/28/2019 8:59am
Some additional photos of cable routing, wiring. Not sure if the wiring is original, looks to be but I can improve upon it.









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sandman768
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sandman768 10/1/2019 9:27am
10/1/2019 9:27am
Everyone “s favorite...... cleaning & greasing swingarm & linkage bearings...luckily these were all very clean and in excellent condition.


sandman768
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sandman768 10/1/2019 9:30am
10/1/2019 9:30am
Pretty cool you can still order this complete OEM clutch lever assy..

NiekL
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NiekL 10/1/2019 1:57pm
10/1/2019 1:57pm
sandman768 wrote:
Everyone “s favorite...... cleaning & greasing swingarm & linkage bearings...luckily these were all very clean and in excellent condition. [img]https://p.vitalmx.com/photos/forums/2019/10/01/377008/s1200_77F01EFE_FA4D_4558_A51F_05F0EFC556B7.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/01/377009/s1200_50A7643B_3E25_4BF5_9913_C4D86215F2A9.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/01/377007/s1200_DCE461FB_7EB2_43B9_9A3B_D681F276242E.jpg[/img]
Everyone “s favorite...... cleaning & greasing swingarm & linkage bearings...luckily these were all very clean and in excellent condition.


Holy cow, the condition of this bike and the Honda Cr125 you managed to findWoohoo
sandman768
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sandman768 10/1/2019 6:34pm
10/1/2019 6:34pm
NiekL wrote:
Holy cow, the condition of this bike and the Honda Cr125 you managed to findWoohoo
I have bought plenty of losers also, but I have learned...clean & original makes life much easier!
mxsixty
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mxsixty 10/4/2019 2:43am
10/4/2019 2:43am
sandman768 wrote:
Some additional photos of cable routing, wiring. Not sure if the wiring is original, looks to be but I can improve upon it. [img]https://p.vitalmx.com/photos/forums/2019/09/28/376335/s1200_C995EEA0_6453_444A_A29F_38EF382352FB.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/09/28/376334/s1200_D9861325_2CE8_4104_BCFD_4EB520CD3271.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/09/28/376333/s1200_80A5A135_478C_4F9C_9BDB_13D1B1939462.jpg[/img]...
Some additional photos of cable routing, wiring. Not sure if the wiring is original, looks to be but I can improve upon it.









Thanks heaps Sandman for putting up the pics that will help me get my wiring and cable's run a bit neater.
mxsixty
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mxsixty 10/4/2019 2:50am
10/4/2019 2:50am
Here's a few specs on the 1990 KX250 H1
It might help someone out rebuilding one.





sandman768
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sandman768 10/4/2019 4:11am
10/4/2019 4:11am
mxsixty wrote:
Here's a few specs on the 1990 KX250 H1 It might help someone out rebuilding one. [img]https://p.vitalmx.com/photos/forums/2019/10/04/377654/s1200_20191004_191905.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377655/s1200_20191004_192209.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377656/s1200_20191004_192342.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377657/s1200_20191004_191755.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377658/s1200_20191004_191459.jpg[/img]
Here's a few specs on the 1990 KX250 H1
It might help someone out rebuilding one.





Nice post, I don’t have a factory manual for mine, thanks! Way richer main jet that the US bikes...when I saw the main in the carb I thought, this is way too lean, but US bikes came with 160 main...
mxsixty
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mxsixty 10/5/2019 6:14am
10/5/2019 6:14am
mxsixty wrote:
Here's a few specs on the 1990 KX250 H1 It might help someone out rebuilding one. [img]https://p.vitalmx.com/photos/forums/2019/10/04/377654/s1200_20191004_191905.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377655/s1200_20191004_192209.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377656/s1200_20191004_192342.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377657/s1200_20191004_191755.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2019/10/04/377658/s1200_20191004_191459.jpg[/img]
Here's a few specs on the 1990 KX250 H1
It might help someone out rebuilding one.





sandman768 wrote:
Nice post, I don’t have a factory manual for mine, thanks! Way richer main jet that the US bikes...when I saw the main in the carb...
Nice post, I don’t have a factory manual for mine, thanks! Way richer main jet that the US bikes...when I saw the main in the carb I thought, this is way too lean, but US bikes came with 160 main...
I forget what jetting I ended up with in the end I usually wright the jetting on the fuel bowl, don't know why I didn't this time anyways...
The jetting in my bike was way off I do remember it had and still has a N85A needle and still running the No*7 slide pretty sure I went heaps fatter on the main than a 160 and I had to go fatter on the pilot jet it had a 52 in it when I got it, it would take like 10 kicks to start before now it starts in 1 or 2 kicks.
I'm running the timing on full advance and gearing is 14/50 but I should have gone 51 rear.
as you can see my set-up is more the snappy side of thing's I don't race or ride hardpack.

Here's a few specs on the suspension getting the clickers back to stock is a good starting point for us lot with 20/hand H1's that every Tom, Mick and Harry and mates have had a go at the clickers on lol..



sandman768
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sandman768 10/8/2019 1:15pm
10/8/2019 1:15pm
New Kawasaki oil drain bolt & washer... original bolt is just starting to lose its shape.
Do not think the clutch cover was ever removed, basket looks excellent. I may have some pieces cerakoted...

Pit Row

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sandman768
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sandman768 10/8/2019 1:17pm
10/8/2019 1:17pm

sandman768
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sandman768 10/8/2019 1:19pm
10/8/2019 1:19pm
Original rear wheel bearings need replacement, 1 is seized the other is loose

Bent206
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Bent206 10/11/2019 10:32am
10/11/2019 10:32am
sandman768 wrote:
[img]https://p.vitalmx.com/photos/forums/2019/10/08/378513/s1200_D5859581_FC65_49BD_A6B8_65AF4A768BF5.jpg[/img]

That is one minty-looking clutch basket!!! Wow that looks like new.
The clutch cover even looks great. Most old KX's have a dent/crack, leaking oil in that same spot. It hard to avoid with their design and only gets worse as the pedal bushing wears.

Love seeing low hour bikes like this still exist!! Previous owner didn't know what he had.
Keep up the good work!!
sandman768
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sandman768 10/11/2019 11:21am
10/11/2019 11:21am
Bent206 wrote:
That is one minty-looking clutch basket!!! Wow that looks like new. The clutch cover even looks great. Most old KX's have a dent/crack, leaking oil in...
That is one minty-looking clutch basket!!! Wow that looks like new.
The clutch cover even looks great. Most old KX's have a dent/crack, leaking oil in that same spot. It hard to avoid with their design and only gets worse as the pedal bushing wears.

Love seeing low hour bikes like this still exist!! Previous owner didn't know what he had.
Keep up the good work!!
Yes, I was happy to see the clutch parts are looking vgood. If this bike ever saw dirt it was not for very long...the clutch cover had a minor scrape from the brake lever, I sanded it out with 220, then 400 grit. 1/2 price eBay Boyesen replacement reeds installed.
sandman768
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sandman768 10/11/2019 11:24am
10/11/2019 11:24am
I”m debating touching up the frame, too bad PJ1 no longer makes this shade of green...I will see what I can get to match rattle can style....
Pat327
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Pat327 10/12/2019 8:30am
10/12/2019 8:30am
sandman768 wrote:
I”m debating touching up the frame, too bad PJ1 no longer makes this shade of green...I will see what I can get to match rattle can...
I”m debating touching up the frame, too bad PJ1 no longer makes this shade of green...I will see what I can get to match rattle can style....
Just me, but I would leave it! It's in really nice shape as-is and it would be kind of a shame to go over the original paint. I had the same debate with myself over a clean '95 I found with a bit of frame wear. Awesome find, dude! One of my favorite years for sure.
sandman768
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sandman768 10/12/2019 3:09pm
10/12/2019 3:09pm
Pat327 wrote:
Just me, but I would leave it! It's in really nice shape as-is and it would be kind of a shame to go over the original...
Just me, but I would leave it! It's in really nice shape as-is and it would be kind of a shame to go over the original paint. I had the same debate with myself over a clean '95 I found with a bit of frame wear. Awesome find, dude! One of my favorite years for sure.
If I had the correct color, I could touch it up and blend it in easily, but a shade or 2 off and I would have to agree with you about leaving it alone.
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sandman768 10/17/2019 11:52am
10/17/2019 11:52am
Swingarm had some scrapes, whoever thought black primer under the silver was a good idea...Think I found a pretty close color match after a few trips to auto parts store. I left original decals on to keep things as original as possible.


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sandman768
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sandman768 10/17/2019 11:55am
10/17/2019 11:55am
This is one of very few bikes where I did not have to replace foot peg pins & springs, still pretty tight.

sandman768
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sandman768 10/17/2019 11:57am
10/17/2019 11:57am
These 2 lower linkage bracket bolts have a tendency to loosen, if left loose, the frame tabs will tear off.
sandman768
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sandman768 10/19/2019 2:40pm
10/19/2019 2:40pm
Noticed Subframe was loose when I first tore it down, the bolt was loose. I had hoped new subframe bolts would tighten it up but one hole is oval from the bolt being loose, need to visit the aluminum welder...
lumpy790
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lumpy790 10/20/2019 7:30am
10/20/2019 7:30am
The 90’s KX’s were really solid bikes with great KYB suspension and good power and handling

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