Danger UK fuel on/off kit comprises of, of one fuel tap and length of rubber hose.
Fit this on/off tap to your existing fuel cap.
When fitted you can leave your original fuel tank taps in the on position at all times. When you go to the line for racing the Danger UK tap is right in front of your eyes and can be checked visually.
Maybe all Speedway bike should be fitted with this as a safety feature, If you have crashed any Marshall can turn off your fuel. Should your bike catch fire you can easily locate the on/off tape.