My brother in law has a mid 80's Polaris 250.. not sure what model. His lightbulb burned out a few weeks back so he bought a new bulb and it burned out within 5 minutes of running it. Put a second bulb in, same thing.... what should we look for to see what's killing these bulbs so quickly?

 

usually burned bulbs indicate a bad battery so the charging system is pushing everything through any bulbs that might be on. you could also have a bad rectifier/regulator box that is over-producing dc voltage from the stator. i would check your battery first if the battery is good, put a volt meter on the battery and rev the motor up to about 2000RPM's and take note of the voltage reading. should be 13.5v to 15.0v. if its more than that, your regulator is going out

 

Reg/rectifier possibly overcharging? Check voltage at battery also when running and see if past 15 volts,if is then could be the problem. The old round bulbs aren't finicky if touched like the halogen so dont think thats the problem!? IF mid 80's model located under front housing. Rare ocasions stator can be the culprit,but have only had one,but several bad reg/rectifiers. Good luck

 

There's actually no battery in it right now... I assume that's the problem?

 

that will do it. big no no to run em without a battery. its even worse than a bad battery. a bad battery will try to soak up something but no battery will tell the regulator to send all it can to the electrical system

 

should have a battery in it like he mentioned. most likely the bulb is real bright right, and its getting too muck voltage and then burning out for the reasons posted.