One of the things I have always had trouble with on my TIGER 1 is keeping the sprocket centre cap in place without using threadlock or a similar semi-permanent glue, THEN!!!!! a pair of 5mm neo-dynium magnets superglued into the cap inner (the inside rim needs to be filed down to make it a soft fit) then screw the sprocket onto the gearbox output shaft, place the magnet loaded cap over the hole and it will lock straight into place and will never come off unless it is gripped firmly with a pair of pliars.shaun