Rode for 3 hrs, stopped for fuel-Tried to start quad with electric starter, CDI box just clicks- So start it with rope starter. Ride for 1/2 hr.- quad just die's. Again no electric starter function, Start with Rope again. Riding down hard road 25-30 mph-quad backfire's and starts to bog down, down-shift, motor clears and runs fine. Get to stop sign, try to turn key switch for lights position, kills motor if left in position. Ride for 1/2hr.- smaller backfire- then bogs-down-shift again- this time unit just stalls. Still no starter, start with rope again. This was the first time I ever rode quad this long, before just rode around the house. Never had any problems, I'm the 3rd owner. Does anybody have a idea where and what I should start repairing/replacing. New to sport, Thanks in advance for your help.