andyswarbs

My son (lets blame someone else...) filled our Yamaha YBR125 (2008) up and put the petrol filler cap back on incorrectly, in that there is an arrow on the cap that is supposed to point forward. Instead the arrow points at about 8 o'clock. The result is that now we cannot get the cap off with the key. They key turns but the cap does not come off. Is it a matter of brute force and ignorance or has anyone any advice?