Micahdawg

Member
Feb 2, 2001
503
0
So I just bought a 1989 KX250 this weekend for $400.

Good stuff: Front/rear brakes complete and functional. Rims decent (front a little tweaked), tires good enough, brand new FMF pipe/silencer...and the bike is 100% complete except for kickstarter.

Bad stuff: Sub frame is broken, front forks feel empty (not sure if they are tweaked or just need rebuilt), bars are junk, plastic is "just ok", one radiator is really bashed hard.

Now, the motor: I installed a kickstarter from another motor and was able to turn the cylinder over. It felt good on compression. I did not try to start it though, but started ripping the motor down instead.

Removed the stator cover and coolant pours out (there was not much in the radiator). Popped the head off and it looks fine, no debris or bash marks. Pop the cylinder off and the KIPS looks to be working fine. Piston has marks all over it though from contacting the cylinder at one time. The cylinder fells good though, but looks like it has wear marks at different areas around it. No major pits or scores and you can even see cross hatch marks in some areas. The crank was full of coolant and the clutch plates are smoked.

My biggest question is about the bottom end and cylinder. I really don't want to rechrome it and wonder if it can just be honed. Even if some of the plating has worn, can it be used as is? There is no flaking or chipping, just some areas that look shinier. The piston looks so bad though, that I have to wonder if it was one that siezed, but was reused after this cylinder was chromed again (which I know it was). I just don't see how the piston can look so bad, but the cylinder not have major scratches, etc...

Anyway, I'm on the fence. Would be nice to salvage this one, but I'd hate to lose too much money over it.

Micah
 

blanc

Member
Dec 18, 2002
623
0
Replace the waterpump repealer, seals , bearings, bottom end main bearings and seals, new piston, and reeds, she should be good to go! Do things like plastics, chain and sprocket after you ride it for a day or 2!
 

Micahdawg

Member
Feb 2, 2001
503
0

Micahdawg

Member
Feb 2, 2001
503
0
Here is an update for anyone that cares :)

I've got this bike down to every last piece. Split the case last weekend for the first time in my life. The bearings and seals were definitely smoked. The bearings spun roughly and there was coolant in the stator side seal. The only other items that need replacing on the inside is a new water pump drive shaft/gear with new bearing and the KIPS gear (the plastic one that sits above the water pump.

Every seal is shot, but a full gasket kit + seals is only $70.

Crank looked good, the IMS rod looked good. Piston is junk, but I scored a NOS piston for $15. The cylinder looks like it will clean up with a hone, so I had a local MX shop do the hone and pull the bearing off the stator side crank for free.

I am feeling better about the motor stuff now.

I also scored some other items on the cheap:
Subframe = $46
Crank bearings/seals = $34
Factory service manual = $16. (hey, it's worth $16 to make sure it goes back together right)

So I think this will turn out ok. Thanks for the advice guys.

Micah
 
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