My 2007 polaris 450 sportsman used to start with the pull start 2nd pull,now it starts for a couple seconds and stalls ,does this three or 4 x then starts and runs fine,by the way it won't start with electric ,just clicks,any help appreciated.

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.