Newbie here. I just bought a 2012 500 sportsman. The problem I am having is when I start the bike the tach will read 1100 to 1200 or so but then the RPM display will drop to 600 or so. Note that there is no change in motor idle. If the cooling fan kicks on or I put the headlights on the gauge goes back up to the proper reading and functions normal but as soon as I shut the lights or the fan shuts off the reading again drops like a rock. Again normal engine operation. So where do I begin to look for the problem? Has anyone else run into this before? It does have a new battery too. Thanks for your help.Mike

 

Am having the same problem on a 2011 500HO.

 

Rpms are transmitted to the display from the regulator/rectifier. It gets it's signal from the stator. Since you have a new battery is it charging 14 volts at an idle back to the battery. If not,the regulator could be the cause of the problem. If it is charging,then problem could be in the speedo harness or pins in the speedo connector may not have good contact with the display.

 

Thank you. I will check that.

 

Update. the battery at rest is 12.5 volts. When I start it up I have 14.5+/- at the battery. I checked the Battery connection and ground and they were clean and tight. I have disconnected the speedo and plugged back in and checked all connections around the regulator and handlebars for anything unusual and found nothing.The tach is still operating the same way.....

 

Best way to eliminate if it's an electrical problem or a problem in the display itself is with the manual and the speedo section test. Shows you step by step on the 16 pin connector and their functions. If the harness and connector along with voltage isn't the problem,then the problem could be in the display itself.2012 Polaris Sportsman 500 H.O. Service Manual PDF Download

 

Hi just wondering if you got your tach reading right as I am having the same issue with mine.

 

Pull the Yellow with Red stripe wire at the regulator.Use a little electrical grease. Same thing on the speedo connector,use a little grease on it. Yellow/Red pin should be number 7 on the connector. Manual says rpms may vary a little depending on temp and humidity,but it shouldn't be a drastic change or drop.

 

Tried the electricial grease didn't work,still shows about 600 plus-minus rpms at idle but if I turn lights on it reads 1200 plus-minus,this thing is driving me nuts....

 

Have you load tested the battery? Plus what is the voltage reading at the battery while at an idle lights off and also when you turn your lights on? May be something there that could be the problem.