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KTM sx250 2004 weird starting/running problem

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Hello, looking for help. Before my bike ran ok, then it start to dying when it gets warm. Every time it just dies after 5min. I changed stator, coil and plug/plugwire. Now after changing those parts it starts really badly and runs like crap. It would start if put extra fuel to intake or straight to cylinder. But it runs only few second and then dies. Spark seems like its ok, cleaned carb many times, changed left crankshaft seal and changed new gaskets to top end. I think it has good compressions. I noticed, that there was a black liquid in crankcase. Not sure what it is, i think just unburned fuel and oil mixture. (I use 3%) There is also lot of oil coming out of exhaust port dropping on to pipe. Sorry for my bad english, but need for help!

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-replace silencer packing + burn out the expansion pipe?

-vapor lock in gas tank?

-broken or blockage in petcock?

if nothing else works try to swap a CDI from a same bike and see if thats what is wrong. (doubtful but it happens)

 

 

 

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53 minutes ago, billtro11 said:

-replace silencer packing + burn out the expansion pipe?

-vapor lock in gas tank?

-broken or blockage in petcock?

if nothing else works try to swap a CDI from a same bike and see if thats what is wrong. (doubtful but it happens)

 

 

 

Expansion and silencer are new, there is pretty much oil in though.

Not vapor lock in tank.

Fuel flows good thru petcock.

I try that CDI swap tomorrow. I have another used CDI from running bike.

 

52 minutes ago, billtro11 said:

also I've seen bikes run like shit when installing aftermarket light kits that draw too much power from stator.  Any lights on bike?

Yes it has now aftermarket lightning stator. Can i test it somehow with multimeter?

 

Edit. When it dies, there is gas in carb.  Jets are clean.

Edited by Zj90

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  Float height too high?

 

I had an 03 250sx that did the same thing, needed a full carb rebuild and floats adjusted properly.

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56 minutes ago, poldies4 said:

  Float height too high?

 

I had an 03 250sx that did the same thing, needed a full carb rebuild and floats adjusted properly.

 

56 minutes ago, poldies4 said:

  Float height too high?

 

I had an 03 250sx that did the same thing, needed a full carb rebuild and floats adjusted properly.

How can i know when its good? I have adjusted it few times. 

I noticed that my air screw (real name?) thread is broken and it is open like 3 or 4 rounds. I wont go deeper.

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37 minutes ago, Zj90 said:

 

How can i know when its good? I have adjusted it few times. 

I noticed that my air screw (real name?) thread is broken and it is open like 3 or 4 rounds. I wont go deeper.

Air screw is issue #1. Get that fixed, optimum should be between 1 and 2 turns out. 

There is a measurement for the floats in the manual, that will explain it better than I can. 

Buy a rebuild kit for the carb and start there.  

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Fixed that air screw, now it is 1 turns out. Jets are 170 and 50. Bike is still very hard to start but today i get it and drive it few kilometres. Low rpms probably runs too rich but flat out feels like pretty good. Why there is black oil coming out of pipe and cylinder? Clutch side crank seal or case gasket broken?

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3 hours ago, Zj90 said:

Fixed that air screw, now it is 1 turns out. Jets are 170 and 50. Bike is still very hard to start but today i get it and drive it few kilometres. Low rpms probably runs too rich but flat out feels like pretty good. Why there is black oil coming out of pipe and cylinder? Clutch side crank seal or case gasket broken?

Your jetting is too rich, that is splooge, unburnt fuel.  A little is ok, a lot is likely rich jetting.  

 

Start here...        http://users.conwaycorp.net/virtus/page2/speed/jetting.htm

Edited by poldies4

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8 hours ago, poldies4 said:

Your jetting is too rich, that is splooge, unburnt fuel.  A little is ok, a lot is likely rich jetting.  

 

Start here...        http://users.conwaycorp.net/virtus/page2/speed/jetting.htm

I cant believe its unburned fuel, because there is very much of it. Even rear plastics are in oil. Also if i start the bike and let it idle about minute, there is lot of oil in front of engine and on expansion, that oil is coming between cylinder and pipe.

I adjusted float level, its now like bike manual says. My idle jet is #50, probably way too big?

Edited by Zj90

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3 hours ago, Zj90 said:

I cant believe its unburned fuel, because there is very much of it. Even rear plastics are in oil. Also if i start the bike and let it idle about minute, there is lot of oil in front of engine and on expansion, that oil is coming between cylinder and pipe.

I adjusted float level, its now like bike manual says. My idle jet is #50, probably way too big?

Trust me, splooge can be messy.  It could be a leaking crank seal contributing to it as well?  Next time you change the oil measure how much comes out, if it's low then you're probably burning trans oil, but a poorly jetted bike will make a mess of those areas. 

There should be a jetting chart like this in the manual.  It will help to get you close.  I would take the pipe off and clean it, seal it up with new orings and rtv when you install, repack the silencer, the start messing with the jetting.  It's very difficult to jet a bike that isn't tight otherwise, those things will affect your jetting.

image.jpg

Edited by poldies4

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9 hours ago, poldies4 said:

Trust me, splooge can be messy.  It could be a leaking crank seal contributing to it as well?  Next time you change the oil measure how much comes out, if it's low then you're probably burning trans oil, but a poorly jetted bike will make a mess of those areas. 

There should be a jetting chart like this in the manual.  It will help to get you close.  I would take the pipe off and clean it, seal it up with new orings and rtv when you install, repack the silencer, the start messing with the jetting.  It's very difficult to jet a bike that isn't tight otherwise, those things will affect your jetting.

image.jpg

Bike runs now really good if i get it started up, but now the problem is its really hard to start. It need to put extra fuel straight to cylinder from sparkplug hole, then it might start up, not nearly everytime. When its hot it starts first kick.

Is there any other problems if crank seal is broken? I cleaned now expansion and repacked silencer, i was going to ride but cant get it started up today.

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Did the compression test today, after 5 kicks there was 150psi. Its still wont start. Where the hell is problem?

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Maybe the spark plug gets fouled?  If you're sure your carb is good, reeds are good?  When it won't start the first thing I'd do is check for spark.  150psi is low, but it should still run. 

 

When you changed the stator you were sure to line up the timing marks?  It's odd that it runs sometimes, and not others.  Have you checked the coil?  

@Bron-Yr-Aur, I read in a thread in the Kawasaki forum about a guy having similar issues, it seemed like you helped him find the smoking gun,  any advice?

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5 minutes ago, poldies4 said:

Maybe the spark plug gets fouled?  If you're sure your carb is good, reeds are good?  When it won't start the first thing I'd do is check for spark.  150psi is low, but it should still run. 

 

When you changed the stator you were sure to line up the timing marks?  It's odd that it runs sometimes, and not others.  Have you checked the coil?  

@Bron-Yr-Aur, I read in a thread in the Kawasaki forum about a guy having similar issues, it seemed like you helped him find the smoking gun,  any advice?

Spark is always been pretty "small" when kicking. Spark plug, wire and coil are new. Stator is on stock timing marks. Reeds are fine. I dont know about carb, it seems to be good, but maybe it leaks air?

Also i clean the exhaust and silencer, drive it hard today like 30 minutes(then it dies, spark get lost) and there was no oil splooge anymore! Hope it was not tranny oil earlier. 

When i did the comp test it was on 150psi and climbing, i think if i kick it 10 times hard it would be like 170psi. What is normal comp pressure? My piston has now 7 hours, cylinder probably needs plating when changing piston next time.

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Maybe the spark plug gets fouled?  If you're sure your carb is good, reeds are good?  When it won't start the first thing I'd do is check for spark.  150psi is low, but it should still run. 

 

When you changed the stator you were sure to line up the timing marks?  It's odd that it runs sometimes, and not others.  Have you checked the coil?  

[mention=365453]Bron-Yr-Aur[/mention], I read in a thread in the Kawasaki forum about a guy having similar issues, it seemed like you helped him find the smoking gun,  any advice?

Haha thanks for the back pat. You pretty much hit everything I would've. Sounds like he's got several problems. Jetting being one of them. But the OP's last post of losing spark sounds similar.

 

OP, if you are definitely losing spark after the bike warms up, I would check the pickup coil. It's checked by measuring the resistance (ohms) at the connector as heat is applied to the coil itself (next to the flywheel). That being said, it sounds like a fouling plug is also a very possible problem, though.

 

I would strongly suggest a shop or service manual. As poldies already mentioned, getting your carb cleaned and adjusted is paramount. I'm not good at jetting, so I wouldn't begin to guess where to start, but I believe help has already been posted in that department. Believe it or not, the Clymers series is very good. I have one for my KX100 and it not only lists all the electrical specs, but how to diagnose and check the various electrical components.

 

Were I in your situation, I would put all my jetting back to stock. Clean the carb, maybe even professionally. Check the float height. Then I would drain the oil, pull the clutch cover and check the condition of the main bearing. (I'd prefer that any day over pulling the cylinder) Also, I'd check all the gaskets. I agree with poldies that black oil everywhere is unburnt fuel. If it seems rich at low rpms, but the runs hard at higher rpms, I'd open the air screw a little more. That could be why you see a lot of oil out the tail pipe. It builds up, then blows out when you open the throttle hard.

 

It also sounds like you need to replace your O ring exhaust gaskets where the pipe meets the cylinder. Can you see them? Or does it look like the pipe is not fitting securely in the cylinder? I dropped mine in the woods. When I got home, I realized that I had bent my pipe. I could see the orange O rings on one side, and the pipe wouldn't sit squarely in the cylinder. I was getting oil all over the front of my motor. I was able to help it a little by forcing it back into position. But ultimately, I just got a new pipe.

 

Have you messed with your carb lately? If so, MAKE SURE you have everything back the way it was. Some idiot I know spent 6 weeks trying to diagnose an electrical problem on his KX100. Bike wouldn't stay running and began to smoke really bad, couldn't even accelerate. It turns out I... I mean, he, had the carb apart the didn't notice that the needle jet had fallen out while cleaning it. Sometimes the simplest thing will have you beating your head against the wall.

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7 hours ago, Bron-Yr-Aur said:

Haha thanks for the back pat. You pretty much hit everything I would've. Sounds like he's got several problems. Jetting being one of them. But the OP's last post of losing spark sounds similar.

 

OP, if you are definitely losing spark after the bike warms up, I would check the pickup coil. It's checked by measuring the resistance (ohms) at the connector as heat is applied to the coil itself (next to the flywheel). That being said, it sounds like a fouling plug is also a very possible problem, though.

 

I would strongly suggest a shop or service manual. As poldies already mentioned, getting your carb cleaned and adjusted is paramount. I'm not good at jetting, so I wouldn't begin to guess where to start, but I believe help has already been posted in that department. Believe it or not, the Clymers series is very good. I have one for my KX100 and it not only lists all the electrical specs, but how to diagnose and check the various electrical components.

 

Were I in your situation, I would put all my jetting back to stock. Clean the carb, maybe even professionally. Check the float height. Then I would drain the oil, pull the clutch cover and check the condition of the main bearing. (I'd prefer that any day over pulling the cylinder) Also, I'd check all the gaskets. I agree with poldies that black oil everywhere is unburnt fuel. If it seems rich at low rpms, but the runs hard at higher rpms, I'd open the air screw a little more. That could be why you see a lot of oil out the tail pipe. It builds up, then blows out when you open the throttle hard.

 

It also sounds like you need to replace your O ring exhaust gaskets where the pipe meets the cylinder. Can you see them? Or does it look like the pipe is not fitting securely in the cylinder? I dropped mine in the woods. When I got home, I realized that I had bent my pipe. I could see the orange O rings on one side, and the pipe wouldn't sit squarely in the cylinder. I was getting oil all over the front of my motor. I was able to help it a little by forcing it back into position. But ultimately, I just got a new pipe.

 

Have you messed with your carb lately? If so, MAKE SURE you have everything back the way it was. Some idiot I know spent 6 weeks trying to diagnose an electrical problem on his KX100. Bike wouldn't stay running and began to smoke really bad, couldn't even accelerate. It turns out I... I mean, he, had the carb apart the didn't notice that the needle jet had fallen out while cleaning it. Sometimes the simplest thing will have you beating your head against the wall.

Stator and pickup coil are brand new parts, adjusted as manual says. How many ohms it should show? 

I am cleaned carb many times. Float is adjusted as manual says. I ordered some jets, they are allready pretty close stock.

As i said, there is no more oil splooge. I cleanded exhaust and ride it hard, no more oil anymore. Pipe and o'rings are new also. (Pro circuit) Pipe fits good.

Can cdi be broken? 

 

 

 

Edited by Zj90

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Allright, the missing spark issue found.

4rtehd.jpg

Brand new stator &%$#@!ed up. Bolts were installed with loctite. Dont know what happened. Threads are broken and brackets are cracked. 

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