Throttle control comes from a properly set-up bike. The rider has to get the bike to handle as he wants it by feel. He needs to know when the bike will start to move around, when the tyre will reach the limit. Throttle control can be learned, but it must also come from your motorcycle.
Everything must be smooth. You shut the throttle, get on the brakes and turn, then go back to neutral throttle as quick as you can. How early you get back on the gas is down to your bike handling how you want. If it's properly set up you don't have to be so precise to get better drive than the other guys.
The rest is experience. The smoothest rider to make the transition from off to on the gas and then having that finesse to drive the bike off the corner is what makes a champion and everybody else the ordinary guys.
For the first five to 10 laps of a race you see everybody go about the same pace. Then the guy who chose the softer or harder tyre starts to gain or lose. It's possible to run that softer compound with good throttle control: if you're smooth you can make it last. Tyre wear says a lot: clean ripples to the edges are indicative of good suspension and throttle control.
As a kid, I thought the quicker I can get that throttle open the faster I'm going to go. But that's not always true. Sometimes you have to finesse that bike around, there are so many scenarios to compensate for. In a race, everything changes from start to finish - track's got hotter, fuel's burned off, tyres got slicker - there's always something to adjust to.
I learned a lot about throttle control on a trials bike, but also as an amateur dirt tracker. There's not that much grip on the ovals: you approach a corner, keep the bike in a dirt groove, slide the rear more and more, and once you're in that turn you pick the throttle back up and slide the thing round. Apply too much throttle at any point or get back on it too quickly and the bike slides off that groove. It's about balancing the throttle to keep the bike where you want it.
