Someone please help me

Well..first thing first. What carb does it have on it? The vacuum for the brakes should really come from the intake and not necessarily from the carburetor. You need to look at the accelorator pump to make sure it's operating correctly. You could also have the vacuum advance hooked up to the wrong port on the carb. To test this cap it off at the carb and set your initial timing to factory spec, then advance it about 4 degrees without the vacuum advance hooked up and see what it does.