Help 01 CR250R will not start

[flyncr]

Hello everyone – I have a 2001 CR250r that will not start now. It was running fine a few days ago. I pulled the gas tank off to put new gas in, and then I gave it a bath now it will not start. I just swapped the plug out and it still will not start. Is there anything that could have gone wrong during this process?
I checked the petcock to make sure nothing fell in and blocked the fuel line but it flows fine. All the help will be greatly appreciated.

[kxrider]

well try undoing ur fuel bowl jus to see if it has gas then from there test ur plug also not always a new plug works ive had brand new plugs not fire to double check that and make sure ur plug smells like its getting fuel also check ur reeds i mean jus go over basic stuff no matter how basic it is u be surprised how many time someone as has fired up there bike and ran it and it crapped out and couldnt figure out what happened and come to find out to turn tha gas on u kno so jus double check every simple thing

[FPMXer]

Air Filter!!!!!