hi my 150cc quad was working fine then just wouldnt start again solenoid starter just buzzes so i changed it and no joy so i changed starter motor and new batterie and still buzzes lights work but 1bulb has blown at the front any ideas thanks

 

1) Take a meter and measure the voltage right at your battery terminals while trying to crank the starter motor. Your new charged battery should be able to maintain 11.5 volts while the cranking (or solenoid buzzing in you case).

2) Try to start up the quad for 10 seconds (let the solenoid buzz). The quickly feel all the wires and connections between the battery, the solenoid, starter, and the return ground path to the battery minus terminal. Is anything hot? Are the wires uniformly hot over there entire length, or do you find hot spots?

3) Take a pair of jumper cables and jump the quad battery to your car (use extra care to get the polarity correct). Try to start the quad up. Does the starter turn now?