my dads 06 250x has some hesitation from mid to 3/4 throttle when you crack the gas. completely stock except from the baffle removed out of the exhaust. its also hard to start but once it runs itll keep starting right back up. also on deleceration there is alot of popping. im sure this has been asked 1000 times but i need answers immediatley without picking through somewhat similar situations. if you guys can help me out thatd be great thank you!