bike is using way to much fuel

[deathlucky]

its normal for me to get about 270-290km (5L 100km) out of a tank of fuel but the other day i got 210km to a tank and today i got 217km(6.5L 100km) i am riding the same as i normaly ride and i havent done any mods to the bike how ever engine oil did get in to my stock air filter would this make it burn that much more fuel

[The Buddha]

If you didn't screw with it ...
The float tangs bend and end up raising the fuel level in the floats making the bike use more gas. That's the only normal use and wear and tear that can happen.
Cool.
Srinath.

[deathlucky]

how do i check to see if that is it and if it is how do i fix it