2021 ktm 250sxf not starting

weland28
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weland28
Working on a buddies bike who showed up to track and bike wouldn’t start. The bike has 12 hours on it, it has great spark, I pulled the injector out and it’s spraying gas right out of the injector fine. I checked the valve timing and it was correct, the intake valves were in spec, the exhaust were out of spec at .010” (supposed to be .0051-.0071”) which I don’t think would be enough difference to make it not start.

The weird thing is when the injector is installed it doesn’t look like much gas is coming out when you look down the intake, so I sprayed starting fluid in there and still nothing. It doesn’t even try. So it’s making me think it’s no longer sparking when the spark plug is installed? Sounds impossible but I’m lost on this please help
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weland28
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weland28 12/14/2020 8:22pm
12/14/2020 8:22pm
Also the bike has no engine mods, stock ecu, stock exhaust, checked gas for water it’s clean. I also have a 21 ktm sitting right next to it which I swapped ecu’s with and still nothing
XC706 12/14/2020 8:32pm
12/14/2020 8:32pm
Swap gas tanks. Inline fuel filter. Rag in the air boot.
Motofinne
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Motofinne 12/15/2020 12:56am
12/15/2020 12:56am
First thing to do is swap the inline fuel filter.
dbx33
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dbx33 12/15/2020 7:54am
12/15/2020 7:54am
ive got a complete oem 21 fuel pump and two new metal replacement filters for it if your interested. has only 5hrs on it.

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Paw Paw 271
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Paw Paw 271 12/15/2020 8:03am
12/15/2020 8:03am
That exhaust valve clearance can be an issue.

Paw Paw
hypermoto
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hypermoto 12/15/2020 9:07am
12/15/2020 9:07am Edited Date/Time 12/15/2020 9:08am
If it won’t start with starter fluid directly being sprayed, good chance the Plug isn’t sparking when installed.

It’s much easier for a plug to spark in free air than when it’s installed and there’s compression on it. I’ve seen it tons of time, sparks fine when not installed, install it and no more spark. When a plug is bad, not fouled, it can do that.

Try a new plug and report back.

Also, is there any kinks or tight spots on the plug wire when installed?
JBoneMotorworks 12/15/2020 4:35pm
12/15/2020 4:35pm
are there any flash codes coming off the EFI light?
weland28
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weland28 12/15/2020 5:43pm
12/15/2020 5:43pm
Swapped out the spark plug, coil, and boot still doesn’t even try to fire
Tomok
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Tomok 12/15/2020 6:56pm
12/15/2020 6:56pm
Kill switch? Try unplugging? How about ignition coil ground ? Tight?
JohnMatrix
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JohnMatrix 12/15/2020 8:19pm
12/15/2020 8:19pm
If it’s my bike it’s going back to the dealer. KTM is excellent about handling what should be a warranty issue outside of the warranty period. For example, the lower end went out on my 19 250sx at 10 hours and they floated the entire bill. A little persistence helps.
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Factor E
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Factor E 12/16/2020 7:11am
12/16/2020 7:11am
If the dealer didn't unlock the ECU the bike will run for a short time
then goes to locked out mode
Take back to dealer XC2 tool will verify
Unplug tip over and reconnect
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soggy
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soggy 12/17/2020 9:08am
12/17/2020 9:08am
Bring it to the dealer. Ktm would/should take care of it
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redcouch1212
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redcouch1212 12/21/2020 11:03am
12/21/2020 11:03am
This bike still has keihin fuel system? Consider the throttlebody setup, Id back the screw off until the throttle is near closed, and as the bike is cranking move the throttle is very small increments in an attempt to match the appropriate amount of air fuel. Injector can pump fuel into the engine while cranking causing it to flood a bit, so make a proper initial effort and wait/rest. I would attempt this throttle scanning looking for noises that hint that the bike may fire, the throttle body adjustment can be sensitive and using the hot start input can effect and alter the idle adjust/stop. Possible the coil to plug connections are loose and/or poor when fitted, but if you swapped with known good parts then thats not your issue. If there is no trouble code and fuel and spark are there, its syncing that throttle body, Ive sorted this out for a few people seems to be a common issue.

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