Starting out riding a seriously underpowered machine can encourage this bad habit. The difference in progress between zero and full throttle is so little on the machines that young learners are restricted to in some countries that full throttle becomes an automatic response to wanting to speed up a bit. Such behavior spells disaster on a "serious" motorcycle.
Top racers only hold a fixed speed in long sweeping constant radius turns; otherwise they are either braking or accelerating pretty much all the time. The amount may be small into and out of the apex of a turn, but it’s there. The changes may be gentle or swift and are always smooth. It requires sensitivity to messages from the tires to judge it and sensitivity of control to apply it.
Sensitivity
Now I am not suggesting you should ride at the limit of traction on the street but you should exercise the same sensitivity of control to adjust the power and protect your safety margin. The maximum cornering traction is available when the machine has exactly the right throttle to hold constant speed. Accelerating shifts the weight back but the extra traction used by the rear tire is not fully compensated by the increase in weight.
So when you are exiting a turn you need to feed the power in gradually as you straighten up. In an ideal world, the proportion of the available traction you are using remains the same as the tire work shifts from pure braking through a mix of braking and cornering, pure cornering, cornering with acceleration and finally pure acceleration with the machine upright. In the first two phases the front tire works harder, it’s equal in pure cornering then the rear tire gets the major stress.
Masterly Inactivity
As your riding skills improve, the times when you find yourself waiting to get more throttle back on can become frustrating. It is not natural to be "doing nothing" in a turn, you are nearly always busy doing something. First, accept that even trackstars dislike this waiting period. I’m an impatient guy and it really used to bug me.
The best tip I ever got was when I was talking to Bob B, an investment guru. He said he got just as frustrated waiting for the stock market to respond to new information and called the frustrating period of sitting on his hands after setting up his trading positions ‘masterly inactivity’. So now every time I’m itching to get the power back on but know I mustn’t, I remind myself it’s ‘masterly inactivity’ and immediately feel better !
The Throttle Isn’t a Brake
Yes you’ve got engine braking. The bigger the power to weight ratio of the machine, the more engine braking you have available. So what? Sure you can change down early so that we can all hear how your revs are perfectly matched in the downshift, then slow on the engine. But is it good riding ? Not in my opinions. Control of decelerating is far more precise with the brakes. I’m not telling you to stay in a high
gear to reduce engine braking. You want to be in the right gear. If that produces too much or too little engine braking for your purposes, you have the controls to add power or brake. The engine, throttle off, does what it does. It was designed to speed you up not slow you down so use the right tool for the job.
The only time that engine braking gives any real benefit is descending mountains. Holding a lower gear on steep, never ending descents reduces the load on the brakes and prevents them over-heating.
Throttle and rear brake at the same time ? Do I ever do this ?
And The answer is : Yes, for low speed maneuvers.
For tightening my line once into a turn ?
Never, I correct my line by steering.
To prevent speeding up through downhill turns ?
No, I am throttle off and using both brakes gently together, about 2:1 front: rear effort. I have seen simultaneous throttle and rear brake recommended for a number of other purposes that have never worked for me. If you have comments or tips on this subject I would love to hear them.