2 Stroke Price for KTM 125 sx?

Hey yall. This is a 2004 (if I remember right) 125 SX, I am working on it for a guy via another friend and the guy who owns it is wanting to sell it(was in a bad car accident). Right now it will not start, and its hard to trace down, I'm thinking about buying it and then fixing it. What is a good price to offer for this bike? I know working ones around this year go for around 1250-1500. But it in a little rough shape and obviously does not run. Would $400 be pretty low?
 

SRAD97750

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Staff member
Hey yall. This is a 2004 (if I remember right) 125 SX, I am working on it for a guy via another friend and the guy who owns it is wanting to sell it(was in a bad car accident). Right now it will not start, and its hard to trace down, I'm thinking about buying it and then fixing it. What is a good price to offer for this bike? I know working ones around this year go for around 1250-1500. But it in a little rough shape and obviously does not run. Would $400 be pretty low?
Yes, I think $400 is low but also the unknown is scary. I would be under $500 as well. -BIG DAN:thumb:
 
Yes, I think $400 is low but also the unknown is scary. I would be under $500 as well. -BIG DAN:thumb:
Yeah thats the only thing. I cleaned the carb and its getting fuel, its getting spark(although it has a aftermarket stator with no timing marks) and it was getting 120 compression. Which seemed low but still should try to start. I was getting absolutely not even trying to start even push starting... But heard that the compression can effect it that bad. I work on mostly 4-strokes but am getting in to some two stroke engine stuff.
 

SRAD97750

Moderator
Staff member
Yeah thats the only thing. I cleaned the carb and its getting fuel, its getting spark(although it has a aftermarket stator with no timing marks) and it was getting 120 compression. Which seemed low but still should try to start. I was getting absolutely not even trying to start even push starting... But heard that the compression can effect it that bad. I work on mostly 4-strokes but am getting in to some two stroke engine stuff.
For a 125cc that's low. I would expect something over 150psi for a running 125.

Worst case you're looking at a few hundos to rebuild the top end and possible cylinder replate.
-BIG DAN:thumb:
 
Okay. So that might be feasible. I've rebuilt a lot of 4-stroke tops. And I know the 2-strokes are a lot easier. So would that compression actually keep it from starting though? I have a little yamaha badger 80 that is running on 30 psi right now. Lol I am supposed to get a new piston in here in a couple days for that. But like I said i haven't done a lot of 2strokes. Just would be good to know if they are more picky on compression on those.
 

SRAD97750

Moderator
Staff member
Okay. So that might be feasible. I've rebuilt a lot of 4-stroke tops. And I know the 2-strokes are a lot easier. So would that compression actually keep it from starting though? I have a little yamaha badger 80 that is running on 30 psi right now. Lol I am supposed to get a new piston in here in a couple days for that. But like I said i haven't done a lot of 2strokes. Just would be good to know if they are more picky on compression on those.
Compression isn't a go or no-go measurement. There is no threshold of running or not.
My 80cc ranges from 80-110psi
My 250s are 140-180psi
My 500cc with a fresh top end is expected to be 100-140psi.
They are all different, but typically the higher performance the motor is, the higher the compression.
-BIG DAN:thumb:
A compression reading is just guessing if you don't know what compression this motor was making before. It's the actual change in compression over time that shows engine health.
As the compression changes, it will be a consistent trend. Any readings significantly lower than that trend, (even within service limits) should be considered a warning sign.
-BIG DAN:thumb:
 
Okay thanks, So I know that it should be higher compression(< edit), and the starting is indefinitely a top end problem anyway. Worst case scenario I get it and do top end rebuild, which I was kinda planning on being a racing bike any way. Still kind of at a loss for an offer though. Don't want to low ball him but don't want to pay more than I need too. If its a few hundred for a top end and i get it for say $600 I have about a gran in it. I may start at 500..
 
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Okay thanks, So I know that it should be higher, and the starting is indefinitely a top end problem anyway. Worst case scenario I get it and do top end rebuild, which I was kinda planning on being a racing bike any way. Still kind of at a loss for an offer though. Don't want to low ball him but don't want to pay more than I need too. If its a few hundred for a top end and i get it for say $600 I have about a gran in it. I may start at 500..


6-700 would be a good price
 
Back to the engine: my yamahas and honda 125s were usable at 120 lbs. Kick start ok at 100.

What does the plug look like after you try starting it? I am most interested in wet or dry on a fresh plug.
 
Back to the engine: my yamahas and honda 125s were usable at 120 lbs. Kick start ok at 100.

What does the plug look like after you try starting it? I am most interested in wet or dry on a fresh plug.

Hey sorry I just saw this. I will get a new plug for it and try turning it over to see. But the plug that's in it was wet after I kicked it a couple times. Also he said he'd part with it for 775. Little more than I wanted but will prolly end up getting it.
 
I guess it all depends on what happened in the accident and what was damaged. If the forks, frame and swingarm are straight, 775 doesnt sound so bad. the only drawback to a damaged KTM is that unlike yamahas and hondas (yellow and green too for that matter) you cant find lots of wheels and forks.

If the plug is coming out wet then of course it is flooding. If it lay on its side etc for a long time due to that accident you may have a crankcase full of oil and fuel. the carburetor float needle probably was leaky to begin with.
 
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