I have a 2002 500 sportsman I was out riding last weekend and the negative battery came loose and the bike stalled. I do know this bike should run just fine without a battery connected, I checked the voltage when running and it's charging at 14 volts. Also when I run my winch I can only use it for about a minute before it drains out the battery and starts causing the motor to bog and eventually die. What could be causing this it's starting to drive me nuts

 

Start at the easy stuff first. Charge the battery and have it load tested. It may have been on its way out even before the neg cable came loose. If it shows ok(under load voltage is at least 9.5-10 volts) then pull the black wire from the cdi and see if that helps. If it does you could have damage either the cdi kill circuit,have a wiring problem from left control switch or ignition switch or wiring. Easy to damage electronics when cables come loose. Plus I'd double check the regulator after you either check/replace the battery even though you said it's ok as it's easily shorted. Not a bad idea to check the pick up coil resistance while you're at it. Around 97 ohms on the white and white/red wires leading to the cdi. Plus here's a stator check for the heck of it. Which ever one is your application.

Alternator stator coils
Sportsman 400 (2001-2002 and early 2003)
"Exciter coils"
Green to red 3.2 ohms
Green to black/red 446 ohms
"Trigger coils"
White to white/red 97 ohms
Sportsman 400 (late 2003), 500 and 500 H.O.
"Exciter coils"
Red to black/red 1.9 ohms
Red to ground Infinity
"Trigger coils"
White to while/red 97 ohms

 

Forgot to mention has a new stator regulator and pulse coil all rm stator. Also is hard to start sometimes unsure if it's related but sometimes when I use the electric start it will crank and crank how but not start just coughs with each stroke like it wants to start but doesn't

 

I'd still do an electrical check on the pulse coil and pull the black wire from the cdi. Plus will it recoil start? Some people have been able to do that,but wouldn't electric start. Even though it's a new stator/pick up coil,check the pick up gap to the flywheel(.016-.040) and resistance. If it's able to recoil start,could be like what this guy had to do.http://forums.atvconnection.com/pola...ml#post3155476 Also doesn't happen often,but while in the flywheel area,remove the flywheel nut and see if it's sheared a woodruff key.This can throw timing off.

 

Found the problem. Had it running earlier and turned it off couldn't get it started again just cranked but no go, unhooked the black wire from cdi and it fired right up and running perfect even with battery unhooked, only issue is now I can't turn it off lol. What do I need to replace to fix this? Thanks opt

 

You either fried the cdi kill circuit when the battery cable came loose or the kill wires from the ignition switch or left control switch may have shorted that tie into the cdi kill wire. Possible either one of the switches may be faulty also. You just have to start tracing wires. You can ohm out the ignition switch pins,plus the connectors and pins on the left control switch. Also not uncommon as I mentioned that the cdi itself may be damaged when this happened. The manuals trouble shooting guide starts at the black wire from the cdi on it's checks,plus the wiring diagram can help.2002 Polaris Sportsman 500 Service Manual PDF Download

 

Bikes been working perfect been driving it all the time starting first click until yesterday I tried to start it and no fire checked all connections everything was clean. Checked pulse coil all looked good except the magnet was rusty on the fly wheel I cleaned it up put it back together and got 4 good sparks then nothing again. Left it as is over night tried again today and it started right up no problem. What could cause this intermittent fire that randomly comes and goes? I don't trust taking it anywhere like it is

 

Again have you load tested the battery? Plus when it is running what is the voltage reading at the battery at an idle? Doesn't need the battery for ignition,but if the battery is weak,the starter can't turn the engine over fast enough to get a good spark. Also if it's not charging at least 14 volts,the regulator could be the problem. Plus can you recoil start it ok?

 

Battery is couple months old , reads 13.8 idle goes to 14.8 when revved up.

 

Being fairly new doesn't mean a battery can hold a charge. I've had new ones doa straight out of the box. If you pull the black wire from the cdi when you have problems cranking it will it then start ok? Intermittent problems like this are usually wiring problems from the switches or their wiring or the cdi kill circuit itself.That's where the trouble shooting and electrical resistance checks along with the wiring diagram from the manual can help you narrow down what's causing the problem. Pita I know.