Ah, that's the tricky bit of pre-setting both exposure and focus, by half-pressing the shutter looking at something which is at the same distance from you as you guess the rider will be, and also which is sorta "average grey" ie not too bright or too dark (or if you can use a full manual mode, preset the aperture and shutter speed to give you a correct exposure), say something like the road or grass works ok. Use a reasonnably fast shutter speed like 1/500s or faster (for this you'll need to increase the ISO if you can if it's getting dark, like I had to do on some which makes the pictures a bit grainy - I could've tried using the flash too but I didn't want to bother the racers), watch the rider coming through the screen and fully press the shutter at the right time, you can pan with the rider's movement which helps keep him sharp (and blurs the background). It might all sound complicated but it is actually quite easy.
But you know I still had to take 100+ photos to get about 30 I like ... and quite a few had just the back wheel of a bike
A race like this is really good to practise as they went round 30 times.
Great looking gazette btw, I'll have a better look at it later today.