I have a 2007 Polaris Sportsman 500 EFI. The only modification to the ATV is an oversized piston in the engine. I notice occasionally at high RPM, say 50+ mph, the battery light will start to flash and the ATV will start to lose power. Once you slow down to below 50+ mph, the flashing will stop and the ATV rides normal. The battery is new. Is there a rev limiter in this ATV and how does it work? Please advise on what I can check to resolve this issue.