No spark at plug how to check cdi unit

make sure the unit has oil if low it will not start and make sure the switch is set to on also check the gas valve is open

cranking is turning over which indicates that the battery and starter is doing the job
cranking but not firing indicates ignition or fuel problems
now that you have the correct terminology perhaps you can get an answer
first test is to pull a plug ground it out or use a spark plug tester crank it over to see if there is spark
Good spark forget CDI and coil so look at fuel
NO spark indicated , check for 12 volts from the ignition switch on the start circuit
Ignition switches have to power wires to the coil
on gives power when cranking and the other continues power when the starter is nor engaged
power in both positions move on to next check
no power from the switch to the coil when cranking --get new switch next check if both wires have 12 volts is the ignition circuit
check for safety micro switches not working right up to the CDI
power to the CDI but no spark --replace cdi
power from the cdi nut still no spark --replace the coil
AS to not available
check after marker as the units are generic and made by electronic companies not golf cart manufacturers so it is a distinct possibility that a cdi from some where else will fit

Try bypassing the side stand switch altogether & also any safety switch on the clutch lever, sounds like some sort of wiring issue or maybe a bad stator plate.

Good chance it has blown the cdi fuse ,alot of Chinese bikes have a separate fuse for the cdi unit,if it's ok I would say the generator is fried if you have had a burned out regulator.so check it for scorched wires.

check the magneto output. Check the coil and spark plug wires with a multimeter.

Could be a few things, spark plug, coil, coil lead, wiring, cdi unit, check the wiring first for damage or disconnect wires, nextcheck voltage with volt meter when cranking engine (ignition on) if no voltage then the cdi unit needs replacing, could even be your ignition switch, a volt meter will tell you everything and find the fault

In most cases the crank sensor generates AC voltage when the crankshaft is moving. You would check it with a volt meter.
How did you test the crank sensor ?

If you can get hold of a timing light, remove both plugs from their holes and the plastic timing inspection plug.
Make sure you connect the plugs into their leads and ground them to the engine to avoid damage to the CDI unit.
Now connect the timing light and crank the engine and check the timing mark while cranking and check for a good spark at the plugs.
Put the plugs back and reconnect the leads, start the engine and run the engine at 2,500 revs giving it a not to hard rev every 10 to 15 seconds until the engine dies. should be between 3 to 4 minutes according to what you have written.
When it dies connect the timing light and try cranking while checking to see if the timing position is the same as the previous check.
If it wont die take it for a run and see if it does the same in a couple of ks then do the timing check while cranking.
If it is the CDI unit playing up the timing light will not flash or will flash at the wrong position.
But before blaming the CDI unit check the OHMS reading on your sender unit as these can fail too.
If the timing is correct when it fails then it sounds like it will be a fuel starvation issue leaning more towards the delivery and filter system even kinked or perished fuel lines rather than a carburetor problem.
Good luck

Hi and welcome to FixYa,

To my understanding, there are only 2 wires from the ignition pulse generator:

• yellow - pulsating 0.5 VAC when cranking; and
  
• white/yellow - ground.
  

A couple more of initial checks:

• IGN +12 on the black/white wires of the ignition coils;
  
• IGN +12  on the 3 wires of the engine stop relay other than the red/orange;
  
• 0 volts on the red/orange (red/white) wire from the BAS (bank angle sensor).
  

Good luck and thank you for asking FixYA.