hi my name is zac wood and im from evington virginia...i purchased a 1997 polaris 425 magnum about a year ago shes been doing good ever since 3 months ago. it started to bog down half throttle and up.. i loose power speed and everything iv tested it and i had about under a quarter tank of gas put in it and it go its speed back power and everything but yesterday when i was riding i put a full tank off gas and it bogged and lost power and speed...iv rebuilt the carb and cleaned it
iv put new spark plug on it with new plug wire
adjusted fuel and air screw to a factory polaris setting (my dads friend did it bc he has a polaris 800)
made sure every seal and hose are tight
i just dont know whats wrong with it i would really enjoy some help because im lost

 

Pull the black wire from the reverse limiter module at the terminal board and see if this solves the problem. Item #37 on the parts break down. If that doesn't help,then pull the cam cover and check the valve clearance. .006 intake and exhaust.Check for exhaust cam lobe wear that was common on the 425 and the early 500s also.Here's an example.Bad Cam Pic - ATVConnection.com ATV Enthusiast Community

 

Thankyou old polaris tech me an my dad will get on it as soon as possible and i will tell you what happens.....we pulled the rev limiter wire already and my worst fear is that the cam is worn

 

Hope it isn't,but a common problem on the engines.