Setting up Brakes on a Bike isnt that easy so here is a little info how I do it. This might not be the 100% proper way but it works for ME.

First the Stock bikes dont have a front brake so you have to rely on the brake of the Motor/Esc on the rear. Switch off any Reverse Gear *LOL*. Then Switch off any type of drag brake or anything that influences the rear wheel when you are in neutral. Start with the lowest brake setting on the Esc. I have a Futaba 3PKS and the brake power is assigned to the ATL dial (this is standard anyway). This way it is easy to adjust the rear brake on the fly with my thumb.
The rear wheel is one of the most important components to keep a bike running (rotating mass). So when you bring this to a halt with too much braking power the bike inevitably crashes.
I start off with a low brake setting slowly increasing the amount when braking the bike in a straight line. It should never lock up the rear wheel. It should only just start to slide. Thats about the maximum the rear brake can do to stop the bike.
But careful usually you brake the bike into the turns. If you hammer the brake at this setting and turn the bike the rear will loose grip and you crash. You will have to learn to slowly reduce the brake input through a turn. Try to find out how to fully apply the brake while going in a straight line and then slowly reduce the brake input through the turn.

It might not be the best way but I learnt this by first using full brakes. Reducing speed towards the turn. Then releasing it and turning the bike into the turn. Then I carefully apply the brakes to slow it down towards the apex of the turn. The bike usually then slightly slides over the rear tire. This way you can also drift through a turn reducing the radius the bike would usually take.

Now comes the SUPERBIKE with the front brake. Here you have to find the right balance between the front and rear brake.

VERY FIRST: Dont start until the front brake works PERFECTLY!!! Spin the front wheel and flip the bike from one side to the other. The disc should just rub against the pads and slowly stop. If something is wrong it will quickly stop or even stop abruptly. The Brake disc is usually a floating type design and then rubs against the left or the right brake pad. If there is something wrong with the disc/wheel connection it will lock up. And you dont want this to happen in a turn. So waste as much time you can to make the front brake work smoothly under ALL circumstances or take the brake off the bike!!

I have the front braking power adjustment connected to the third dial on my radio. Try to find a easy way to adjust both brakes on the fly (even while racing) and learn how to fine tune it! The braking balance can change from one heat to the next and you dont want to go through any radio control menus 10secs before the start

I usually switch off the front brake at the beginning and find the maximum of the rear brake the way I described above. After that I reduce this setting by 50%. WHY? Because the front wheel can cope with much more braking power before it locks up (I am not explaing why, that, here...). Or the other way round: With front brakes the rear locks up earlier.
THEN I switch the front brake on. The amount of the front brake that can be applied is actually limited by the moment a bike starts to nose wheely. Then its too late and the bike will crash. This is because at that point the rear wheel stops (see above) and due to the steering only connected with springs the bike is then absolutly instable. A butterfly in brazil will make the bike crash

How far you have to reduce the front braking power is only limited by:
-how good the bike is when going from straight line into the turn under braking. Some bikes completly wash out over the front as soon as you steer under braking. I might tell you why.... sometime .....
-your driving skills
-how brave you are ;-)

Now comes the tricky playing around. You have to find the right amount of rear brake to fit to the strength of the front brake. Not only that: It has to work over the full range of speed and amount of braking power applied! If the rear is too strong it will slide over the rear and usually highside. If the front is too powerful it will wash out over the front wheel.
And again you will have to learn how to balance the bike towards the apex slowly reducing the amout of brakes.

If its perfect (and your driving skills are) you will be fully braking towards the turn then steering into the turn while slowly reducing the brake. If it is balanced perfectly it will slightly drift over the rear tire continously reducing speed. Once you are trough the apex you let go of the brake and start pulling the trigger.....
And for the perfectionists: At low speeds through a hairpin you can drastically reduce the turning radius by slightly pulling the brake. If its set up correctly the rear (ESC) brake hardly has effect but the front brake turns the fork into the turn because the gyroscopic effect of the front wheel isnt high enough at low speeds. And if you have a Stock Bike and want it to turn in a tighter radius at low speeds: Tighten up the bearings of the front wheel. Just enough to give the front wheel a slight bit of drag....

One more thing: The amount of brakes needed WILL change significantly if you change the weight of the wheels! ... and you start from the beginning ;-)

How to set up your brakes on a 1/5 bike

By Edi Winter