If you're missing the speedo,they're not cheap.PartShark is the cheapest I've found,$295.Polaris 3280363 - SPEEDOMETER,3.38",6-PULSE : Part Shark If it needs repairing and you are capable or know someone,couple articles on this.http://forums.atvconnection.com/pola...ml#post3232409 KA7OEI's blog: Repair of the speedometer on a Polaris Sportsman 500 4-wheeler

 

I was reading this because I too have a lean condition that is causing backfiring and will not rev. Starts great and idles fine. Changed from a Chinese carb it was sold to me with to the OEM and same condition. I checked the valves and they did not need adjustment but the exhaust lobe was 95% gone. Intake lobes look brand new! I am waiting on the new cam but pretty sure that’s why it won’t run