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Old 02-19-2019, 07:43 AM
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Default HOT 350 SX-F

     

I took my first spin on my newly acquired '13 KTM 350 SX-F. On one set of laps, I noticed the bike was acting a little weird (the issues may or may not be related, BUT): it hit false neutrals a couple times, began to feel warmer than usual, seemed to misfire a couple time. So, I pulled off and my first thought was to check fuel level. As soon as I opened up the cap it let out a huge hiss and some fuel. I closed it back up and cracked it slightly to let all the pressure out. Once it seemed safe, I took the cap off to find the fuel was boiling. It was a mildly warm day (by our standards in deep South Texas) at 85-90F. I touched the motor and rads and they were HOT. It only did it this one time all day. I'm not sure what caused it or how I can help remedy it. I will also note that the bike has a bit of smoking at start up and can sometimes crank a little longer to start. Nothing crazy, just not an immediate fire up that I'd expect from a fuel injected motor. The smoking isn't that bad either and I'm kind of undecided on if it looks blue (oil) or black (fuel). I checked and set the valve clearances, but I'm thinking maybe I should check the TPS and make sure it's set right. I did notice some backfiring in the muffler when coasting/letting off the throttle going into corners. Any ideas??
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Old 02-19-2019, 08:20 AM
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Adjust your TPS. Here's a video of it.

https://www.youtube.com/watch?v=f_FZ2tBDjTY
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Old 02-19-2019, 09:03 AM
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I'm no KTM expert by any means but if it's getting that hot I'd be checking the cooling system for issues, as well as the gas cap vent to see why it's building so much pressure in the tank.
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Old 02-19-2019, 09:33 AM
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I'm going to check with a few locals before buying the pigtail for setting the TPS.
I agree, Cowboy. That was my initial check at the track: I let it cool for a while (helped some guy straighten out his bars after a decent getoff), and took the cap off. I then turned it on and the coolant seemed to be flowing just fine when the bike was on. Is there something else I could check on the cooling system? Maybe I could swap the coolant since I don't know the last time that was done.
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Old 02-20-2019, 08:32 AM
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Does that bike have a factory thermostat? I guess it could have just been an air pocket in the system working it's way out, but if you saw coolant flowing then the water pump should be fine. Other than a thermostat sticking closed, unless you have some foreign debris in the system plugging things up there shouldn't be much that would cause the coolant not to circulate.
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Old 02-20-2019, 10:07 AM
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Thanks for the guidance, fellas! I was able to find a local guy with a setup to check the TPS (using a phone charger to supply the 5v necessary). I was unaware that this bike had a thermostat and will look into that as well as looking for any obstructions in the cooling system. Then, I'll let y'all know what I found
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Old 03-26-2019, 09:29 AM
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Finally got the TPS adjusted. From what I see these do not have a thermostat. I'll wait until I get around to riding again and see what happens.
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Old 03-26-2019, 11:57 AM
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A dirty fuel injector will cause it to run bad, lean and over heat.
The popping exhaust can also be caused by a bad exhaust gasket at the head.
These bike are also known to get a crimp in the fuel delivery line at the fuel pump which can also cause these issues. Check it.

Paw Paw
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Old 03-26-2019, 12:43 PM
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Quote:
Originally Posted by PawPaw View Post
A dirty fuel injector will cause it to run bad, lean and over heat.
The popping exhaust can also be caused by a bad exhaust gasket at the head.
These bike are also known to get a crimp in the fuel delivery line at the fuel pump which can also cause these issues. Check it.

Paw Paw
Will do. Thanks PawPaw! I do know there is a spring missing on the exhaust where it meets the head. I need to take care of that asap.
Where should I check the fuel line? Where it comes out of the tank? Inside the tank/pump assembly?
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Old 03-26-2019, 07:05 PM
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The line that kinks is inside the tank and hooked to the fuel pump.

Paw Paw
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