Motorized Bicycle Trouble ShootingUse this area to post problems that may arise, if you could use some help in figuring out what is wrong with your engine and what needs to be done to achieve top performance.
Re: 80cc motor is back firing , jerking and dying.
Likely to be the ignition system. See if you're getting spark. If not, use a multimeter to check the resistance of the magneto. Check the condition of the spark plug, and also look for burning between the spark plug and wire. It's most likely the cdi, but at least test the other components before replacing any parts. You want to be sure.