I have a 2007 arctic cat 500i 4x4 atv, no spark, replaced the plug, starter relay and ignition coil, still no spark. is there a way to test the cdi unit?

Pour a few tablespoons of Automatic Transmission Fluid (ATF) down the spark plug hole into the cylinder. Leave it sit with the ATF in it for a few days. With the spark plug still removed, crank the engine over a few time to expel the ATF from the cylinder. Turn the key off, spray a light squirt of starting fluid or carb cleaner down the the spark plug hole into the cylinder and install spark plug. Try and start as you normally would.

Soaking the cylinder a few days with the ATF should dissolve any rust/corrosion that may have frozen the piston rings to the cylinder wall. If still will not crank over, then I would suspect the starter is corroded or bad. Of course it could also simply be a bad starter relay. To test this I would use a jumper wire from the battery positive side to to the starter side of the starter's relay. If the starter whirls to life, then this would confirm the relay needs replaced. If the starter still will not engage then you're back to either a bad starter or the piston being froze in the cylinder.

coil you can test if you have a coil tester but doubt you do. CDI cant be tested. could also be a pick up coil on the stator, ignition switch, kill switch, tether if it has one.

first thing is make sure connections are tight.check ground wires(black cable/s).might be a bad coil lead.to the spark plug

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change the plug and make sure you are getting a good spark.

u must always hav 12.6 v for a coil ignition--u cud hav hurt the alternator - the relay is burnt too probly - the spark area and wiring seems to hav issues--get a clymer manual for detaild engine work--cdi is capacitor discharge ign

Engine seized ?. Will it turn over if you remove the spark plug ?
Here are the service manuals for all Arctic cat ATVs

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coil gone bad or broken wire. kill switch ?
here are the service manuals for all Arctic cat ATVs

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Weak battery, bad starter. burnt fuse. here are the service manuals for all Arctic cat ATVs


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If your engine is starting slow and the battery is good, your starter may be on its way out. Remove it and bench test it, or while starting if it becomes hot to the touch, it may be time to replace