I have a 2004.5 sportsman 500 with 1800 miles on it
I have a problem when I hit about 30 miles a hour at about 45 to 5000 rpm it seems like it starts to miss and back fire just like you were going in reverse with the rpm limiter had the sparkplug replaced and the carburator cleaned and still no difference. Would it be the reverse rpm limiter causing it to do that in high range. Its a ongoing problem ever since its been brought out.
Also when driving in high its like it miss fires and I dont know what it could be.

Appreciate any information. Thanks!

 

any water in the gas from moisture sitting. how did the plug look?

 

After looking at the plug it looked dry but it was black
also i forgot to mention after reving it up when it was sputtering i pulled the chock out and it didnt do anything. but when idleing i pulled the chocke and it died. It has lots of power up to 30 miles a hour then starts missing and sputtering really bad.