Past the baffles, high spots and low spots in the tank?

 

Take it off, fill with hot soapy water, slosh around, repeat, rinse, rinse, put a half gallon of gas in and slosh around, dump that on the cracks in the driveway where the pesky weeds grow. allow to dry. reinstall and hook up, fill and go. Of course I don't have EFI, so it may be different for you.

 

Take the tank off remove cap and tank filter assembly drain all gas you can then I used low air pressure to blow tank out. Do this away from your bike and any open flame or ignition source. I have only had to do this once so far and it worked great.

 

I do not put crap in it, but to get all the gas out without removing the tank I remove the petcock and lean the bike over.If that does not do it for you remove the tank and keep shaking and rolling the tak around to get it all out.Good Luck !

 

siphon it out, shake bike, siphon again

 

First question all should have asked is "Is it fuel injected?"......Original poster needs to wait on trying any suggested fixes till he supplies that info.