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Gas in Ktm header pipe

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Hello, my 2013 ktm 125sx wont start and there was gas coming out by the header pipe so i took the pipe off and there was gas in there.   why would gas being going there? how do i fix it so it will start again?  i checked the plug and it gives a blue spark.

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Sounds like you left the gas on and your float valve allowed fuel to leak past it and flood the engine. Turn the gas off, leave the expansion chamber (exhaust pipe) off, and kick it until it's purged. You can pull the plug cap to ensure it doesn't fire, but it probably won't cause much trouble even if it try's to come to life, you can just mash the kill switch. After you get the bulk of the raw fuel out, leave the pipe off and let it air dry for a couple hours. While you're waiting, take your carb apart and fix it. Either it's just dirty and the float valve won't completely close or the float or valve is bad. If you DID have the petcock (gas valve) turned off and this happened anyway, then you need to fix that too...

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I that today and I took apart the carb and cleaned it and I put everything back together and i start cranking and it comes out of the header again. I haven't even got the engine running all the way yet

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Either your float is bad, your float valve is bad, or you didn't get it clean enough. Couple things: fill a bowl or cup with water or gas and drop your float in it. Does it indeed float? If it sinks, replace it. Also, most modern bikes no longer run an in-line fuel filter (4-strokes not being germane to this conversation), but you might want to add one. If you have a bunch of sediment in your tank, it could be the root of your issue. But regardless, your float is not functioning properly...

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Your crank case could be full of gas. Pull your spark and turn the bike upside down and turn the kickstarter over buy hand.

Edited by GreenMT_Rider
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thanks. i got it.  i turned the gas off again and cranked a bit then slowly turned it back on while cranking.  and it is working good now again.  thanks for the help!

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I have a horror story about this.  81 Yamaha 425.  Kids sat on the thing and somehow the fuel got turned on.  Filled the lower end and the pipe.  I took the pipe off and turned it over by hand.  It spewed fuel every where.  Then without warning it fired and started.  Flames shot out the exhaust and caught the fuel that was on the bike and garage floor on fire.  F*&K!!  Drug the bike out the garage door and tried to put the fire out with my hat.  I loved that hat, but it too caught fire.  Finally got  the fire put out.  Wasn't the first time I had fuel in the lower end.  Had a 72 CZ with a low pipe do that, but it had a drain screw in the lower case just to drain it.  Drained it and fired it up.  Oops the low pipe was also full and blew gak all over my truck.. 

Edited by zilla
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oh wow that does sound like a horror story. i fired mine up and drove it a couple hours that day and it worked perfectly. still working good thankfully.  i didnt get the fire experience like you did. thankfully

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