I found a pocket rocket in a junk pile. All the plastic is gone but the rest is there. When I turn on the on-off switch it lights up and so does the light on the throttle but the bike does not run. What could be the problem

if it is a pile of junk why are you wasting time trying to fix it ?
with out details as to make , model , year , type of equipment a description as "a pile of junk" you will not get worthwhile answers except to just junk the junk

The off and on switch lights up but will not start.

try squeezing the brake lever first, some have a safety switch in the brake lever

did you check the batterys with a multimeter to make sure they are putting out at least 24 volts?

The choke is on the carb. Check if the carb set screw is set right, turn it all the way in and then back out 1 1/4 turns. then fine tune by 1/4 turn increments.

check your buttons lift centerconsole look for bare wires cap or tape up. get buttons at junk yard or try to fix yours get goo gone open switches with small flat head clean springs and ball bearing. be gentle plastic insides break easy these switches break all the tim e go to junk yard and stock your pockets full

Did you ever solve this problem?

there is a button on your brake pedal lever that while braking gets depressed, and turns on your brake lights. Now this component is a plastic piece that can get knocked loose rather simply. You either need to re-secure this component, or replace it

(you can get this part at any junk yard for nothing more than some pocket change)

The other screws are behind the woodgrain panels on either side of the speedometer cluster. The panels are held in place with metal clips and are difficult to pry loose. I did it by using a small plastic wedge that I found in a junk pile and once I had a place to start, I worked each corner of both panels until pried out. These panels could break, so go slow and be patient.

Try this link I found my instrustions her after leving them in a pocket and the wife washed them