Ditto on the carb. I still have an 06 SP450. The carb adjustment and cleaning will make it scream! Everything else recommended is good too! IMO

R'

 

Where do i get the kit at? Should i put new jets in it too?

 

ok i started pull my ATV a part today and i found the air filter and air filter box was full of oil and gas so some how the carb is getting to much gas to burn and it is back pressuring into the air filter. what could be causing this?

 

ok i started pull my ATV a part today and i found the air filter and air filter box was full of oil and gas so some how the carb is getting to much gas to burn and it is back pressuring into the air filter. what could be causing this?

 

Check your carb vent tube for tears, kinks, or blockage. I would drop the float bowl as well, you may have water in it. Change the fuel filter too. Make sure the crankcase is venting properly.

 

you may need to rejet your sportsman.
My 600 was bought from someone with higher elevation, and i live in the city.
It bogged down and was told to rejet it, and it worked!