Remove the lower cowling "plastic cover" and about 1 - 2 cm from the key lock there is a small round hole, put key in and turn to position 2 whilst pushing in the hole a piece of hard wire, it should depress and pop the lock out, be aware that you may have switched your ignition to the on position, inserting a small blade screwdriver you can switch the ignition off afterwards.
If you have lost the key or the barrel has seized, carefully use a 1/4 HSS drill bit then onto a 1/2 HSS drill bit, drill the top few millimeters only this is hardened, after that you should feel the drill "notching" through to the first disc tumbler, remove and swarf and disks with a pick you should be able to pull out all 6 disks and remove the small round bar in the lock barrel "which only drops when all disks are aligned", insert a screwdriver and rotate to position 2 and depress removal pin, now withdraw lock from housing.
Wittybebop
August 2008