Good day,
my 500 HO sportsman idles fine, runs fine, but when holding pretty much full throttle out a nice dirt road....she sputters. any ideas. I have to back off the throttel and she seems fine, but full throttle....nope!
oh yeah, new spark plug.....

 

air,filter? check and make sure vent tube is hooked up at air box

 

Is there a rev limiter in foward gear also on a Sportsman? I know there is for reverse.
May just need a carb cleaning.

Change the plug and run some Seafoam through a tank of gas and see if that helps.