I agree with Vistaman, you remove the shifters and its going to make it real hard to ride when you're not using the motor. Here's how to clear some of the clutter and keep your rear shifter:
Your front derailleur will most likely have to be removed to make room for the engine, so that shifter can go.
Next, get a dual-pull brake lever and put it on the right, so your left side isn't cluttered with two levers (clutch and brake).
Your right side now has a throttle and brakes, to make it a little less cluttered, move your rear shifter to the left side, maybe even switch to a twist shifter if you don't already have one.
Right side with throttle and dual-pull brakes:
Left side with clutch and twist shifter: