Recently got a sportsmen 500. the guy said battery needed replaced so replaced the abttery and now it wont stay charged. charge it up and within a few days its dead and will barely start the quad. the display will not show the tach or the hours sometimes the gas gauge will work other times no. wat could be the issue. when battery does die it will pullstart. New to having a quad so any help would be great or even were to start or wat to check?