Author Topic: My 1990 KX250 Motard Build  (Read 12105 times)

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Offline LukeG

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My 1990 KX250 Motard Build
« on: February 02, 2015, 05:34:50 PM »
I finally thought it was a good time to share what I have been up to with my 250 since I joined. I bough a 1990 KX250 from my father in-laws neighbour which had been parked for about 8 years. It was sitting in a little garden shed getting full sun on it every day. The forks were absolutely cactus, the outer tube on the uppers was starting to oxidise and corrode, they were coming apart as if they were cast iron. Anyway here's how the bike looked when I brought it home.




My plans for the bike are to make it into a road racing motard so I can use it in period 6 historic racing. I already have a DRZ 400 that I raced until on of the crank bearings let go mid race. Everyting on the bike must be period correct so I needed a decent set of forks to go on it. Ebay scan and found a nice pair in the UK. Took the newer forks and the shock to the local suspension guy and asked him to do what he could with them to make them better for road racing.

Things like this are always a nice thing to find!


I tore the bike down as best I could, half the bolts were rusted or the threads stripped. The top end actually looked pretty good but there was no coolant or oil in the thing and the crank seals looked well past their use by date.









1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #1 on: February 02, 2015, 05:44:09 PM »
I plan on getting the frame, sub-frame and shock mounts powder coated but I need to make a new mounting tab for the radiator and get a few holes in the bottom of the frame repaired before that happens. The engine has been completely stripped and I am off to get the cases repaired and vapour blasted some time this week. The engine looks like it has had a hard but loved life. The PO just putted around on it through the bush. What happened before that I don't know. All I know is the main bearing holes in the cases have steel bushes in them, there is some weld repairs in places and there was about 1/8 of an inch of sealant between every mating surface.
I will do some more updates tomorrow.
1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline sandblaster

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Re: My 1990 KX250 Motard Build
« Reply #2 on: February 02, 2015, 07:12:48 PM »
Cool build Luke.
Vapor blasting will make those cases look better then new  :-D
Post lots of pics  8-)
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #3 on: February 08, 2015, 07:25:34 PM »
Can anyone please tell me the colour Kawasaki painted the swing arm back in 1990? I want to make it look original from a distance, I know it's grey but what shade, mines too scratched up and worn out to get a decent sample to colour match.
1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline Brute

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Re: My 1990 KX250 Motard Build
« Reply #4 on: February 09, 2015, 07:57:50 AM »
Man! I hope you got a good deal on it. It looks a bit worn! Course projects don't always make sense on the 'money' end of things. I probably have twice into my KX5 street legal SuMo what it is worth.  :-o
Try and not do that any more though.  :-D
Good luck with the build and keep the pics coming!
Things Are More Like They Are Today Then They Have Ever Been Before...

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #5 on: February 14, 2015, 10:21:27 AM »
Thanks brute, the bike cost $300. I have been keeping an eye out and there was a nice looking 90 went for just over $4000 on eBay last week.

So I spent nearly an hour at a local paint supply shop trying to match the swing arm colour, I found an auto colour that was very close and has a little bit of metallic in it. I think it will look good. I am taking the swing arm to get soda blasted Monday and I will be trying to get the engine parts vapour blasted this week as well. The guy I want to use is a short hour and a half drive away on a good day.
I got most of the engine bearings from a local bearing shop, there were a couple they didn't have, so I placed a large order from Partzilla. I needed new side power valves as they were looking pretty worn. The valves for the 93 are no longer available but they are all but the same through to 02 just the slots are a different size. They are actually smaller on the later valves. The pinion gear is also worn but it is no longer available. I found an alright looking one online, so we will see how that works out.
I have taken heaps of photos for my own reference so I will post a few up when I get onto a PC.
1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #6 on: May 21, 2015, 05:19:38 PM »
Been a while for updates on here. Progress has been slow but I am getting there.

Got the swing arm soda blasted ready for painting, tried my best to colour match to OEM. Just need to sand and clear coat it.


My new Lectron carby showed up today.


Bought a ton of stuff off fleabay and the likes.



I dummy fitted a 92 crank into the 90 cases and it clears also a 93 and 99 cylinder will bolt onto the cases. I picked up some brand new crank halves, so they along with the 93 cylinder and head have been sent off to Pinsonnault Racing to get Todd and the team to work their magic. 295cc of goodness coming up. I have a 4 piston Brembo supermoto caliper to go on. Forks and shock have been rebuilt and setup for supermoto. I picked up a PSI and FMF Fatty pipe, still not sure which one I am going to use yet, I think I will let the butt dyno figure that one out. No pictures of this stuff at this stage.

I also managed to get my hands on a factory green powerband!  :-D
1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline Foxx4Beaver

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Re: My 1990 KX250 Motard Build
« Reply #7 on: May 21, 2015, 08:01:00 PM »
that carb is f**king sweet! :mrgreen:
Excuse me, ma'am...but you've got extremely nice legs!!!...what time do they open???                                                                                                               https://www.youtube.com/watch?v=n8tCgN3aryQ

Offline umberto

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Re: My 1990 KX250 Motard Build
« Reply #8 on: May 22, 2015, 02:40:57 AM »
I also managed to get my hands on a factory green powerband!  :-D


That's what a powerband looks like.  I could never find the one on my bike.   :-D
« Last Edit: January 06, 2018, 01:57:13 AM by umberto »
Perhaps I have a dirt bike addiction?

03 KX 250/88 KX 525/2017 KX250F - Goliath
17 KX250F/04 KX250
04 KX 250 - Lunchbox's Bike
05 KX 125/144

Offline sandblaster

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Re: My 1990 KX250 Motard Build
« Reply #9 on: May 22, 2015, 03:13:21 AM »
 :-D
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #10 on: September 19, 2015, 09:09:41 PM »
It has been a while since I updated this thread. Progress has been slow and steady. My cases were pretty trashed and locally going to cost me a lot to fix them up. Fortunately I found a set of cases in the states and had them shipped to Blaster. Mike and his team welded the sump plug hole and cleaned the cases like new. He also sent me a tin of Timesaver.

[imghttp://i763.photobucket.com/albums/xx276/aussiedrzguy/1990%20KX250%20Restoration/KX250%20003_zpstds0myps.jpg]http://[/img]

I sent off my 93 cylinder and 92 crank to Pinnsonault for boring, porting and a rebuild. I was very happy when I got them in the mail. I didn't take any close up pictures yet!


1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #11 on: September 19, 2015, 09:19:51 PM »
I also received my package from RSW Racing.



13mm offset triple clamps!

I bought myself a little arc welder as I need to repair the frame in a few places.

Also it's an advantage to work for a large manufacturing company when you need to make a new bracket with a nut projection welded onto it.


Also welded up the foot peg brackets as they are really flogged out. Nice new cast titanium pegs to go in there when done.

1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #12 on: September 19, 2015, 09:43:44 PM »
And of course lots of new little bits and pieces.




I have painted the swing arm, the colour I ended up using was an auto colour called Iceberg Mica. I like how it came up. It was a cold winter by Australian standards so it made painting things difficult but after a few goes and a lot of sanding I am happy with the results. Just need to apply the Uni-track decal.


I also bead blasted and painted the steel swing arm linkage plates as they were a little rusty and need a pretty up. Also to get some more arc welding practice in, I made a little frame to hold the engine once I get the cases together.


I have this week off work so I am hoping to get the frame sand blasted, then I am going to crack test it and repair any rusted areas and cracks. I already cut one piece off the frame as you could see it was all rusted out and I wanted to know what size tube I would need to place it with.


You would be surprised how hard it has been to find replacement steel tube off the shelf in my area so I turned up some.

1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #13 on: September 19, 2015, 09:47:24 PM »
Also where the rivot goes into the subframe for the plastics has been drilled out and a nut and bolt used. I will be getting the holes welded up and I have a new rivot to go in there. The seat mounting holes are also stripped out so I am going to rethread them before sending both frame off to be powder coated.

1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard

Offline LukeG

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Re: My 1990 KX250 Motard Build
« Reply #14 on: September 19, 2015, 09:53:02 PM »
The great news is, as I am typing this up, I got a text message on my phone telling my I have won one million pounds!  :-o They just want all of my personal details so I can claim the prize.
Seems legit!!!
1990 KX250 - Wanna be road racer!
2007 DRZ 462 Motard