If you are getting gas into the float bowl, I would say your jets are clogged. Take the carb off, pull the idle and main jet out, soak them and blow them out with air. Make sure you can blow through them before reinstalling them in the carb. This should solve your problem.
A single cylinder 2 stroke 249cc engine with a Keihin PWK36 carb.
The 450 SX is a single cylinder 4 stroke, so no you do not mix gas.
First-check compression second-see if fuel is getting to carb. make sure your fuel mixture is correct 40-1 to 60-1 for a two stroke ktm check your mixture screws on carb more then likely one of them is out of adjustment. If all that don't work then you probly need to rebuild your topend
Loosen the clamp on both sides of the carb and slowly work it out of the boots. As it comes loose from the boots, plug the intake boot that goes to the cylinder with a clean shop rag so no dirt or junk can get into the boot. Next, unscrew the top of the carb and carefully pull the slide out of the carb. You now have your carb free to work on.
It does not. My 09, as well as all other year KTM atvs, have a carb. Same goes for the 500's.
Check your gas/oil ratio, check your plug and make sure your filter is clean. Next check your carb and make sure the jets are not partially plugged. If all of this checks out, my friend, it is time to rejet your carb.
Just as long as you have enough gas to fill the float bowl on the carb is all that is needed to start a bike. It won't stay running long if that is all you have though, maybe 2 minutes.
take off the carb. on the botoom of the carb is a bowl take screwsa out and the big jet in the center is the main jet. remove with a flathead screwdriver
1997 300 mxc manual says 40:1 to 60:1 i find with the stock carb settings my bike runs just right at 50:1
You need 3 things for your engine to run, gas, spark and air. First thing I would check, you may already have, but check to see that you have gas flowing into the carb, if you do, then pull your carb and check the main and idle jets to make sure they are not plugged up. If this doesn't work, disconnect your kill switch.
KTM recommends unleaded fuel with 91 octane rating.
In the center of the head (on top of the cylinder).