Will not start, battery is fine - Polaris 2005 Sportsman 500 H.O

It sounds like the battery is worn out. It is lacking Amps and Volts. Or the battery contacts are dirty or corroded causing a bad contact.

check battery most likely dead

When I was in the shop, we called things like this 'chasing the ghost' lol.
You'll have to start tracing wires and checking all connectors and contacts and fuses. Test light and voltmeter will be your best assets here as well.

Start at the battery and go from there. I'm unaware of any 'known issues' with the 2006 cats fitting that description but I'm sure it'll be something simple after you spent a large amount of time chasing it...it usually is. Good luck!

Clicking sound from the starter relay in my many years at a dealership is usually a sign of low battery voltage. Starter failure is an amature guess.. yes why though possible extremely unlikely.. easy steps before just being a parts replacer.... first make sure battery is charger. If battery is charged that does not mean it has 12 volts when a load is applied it only means it's full charged but doesnt mean its good..hook up jumpers to a known good battery (IMPORTANT) if you use a car or a truck that's fine just do NOT START the vehical connected. ATV cant handle the amperage from the alternator.. if it starts it a bad battery.. if it still clicks the starter can be tested as well as making sure the motor isnt seized. Test and continue to test.

If battery has full charge, then the current is not reaching motor. U need to check all switches, relays etc. that are in between the battery and the motor. Also check the battery connections for corrosion.

Test the battery with a voltmeter, if good, check connection to battery. Has to have a real good ground.

The battery is flat, the alternator is not charging the battery.

just because battery shows charge doesn't mean it has the load to turn over engine, have battery load tested. it might be bad.

ok when you say it wont start does that mean it will not turn over or does it mean it does turn over well but will not fire

Could be time to replace battery, this is most likely the culprit. These fourwheelers are very picky when it comes to low power. Your starter is also most likely just fine, the clicking you hear is the solenoid on the starter, so your battery has some juice, but not enough amps to turn over the starter. Also If the fourwheeler has sat for a long time then you may just need to charge the battery. The 2007 is most likely fuel inject which uses even more fuel when running and it also has its own computer kind of like a PCM in a car or truck. These all need a good supply of power and the stator which is like an alternator usually needs the help of a fully charged battery to keep everything running properly. Also note, once you get a new battery or charge it in some cases the ATV should run smoother.