I have a 09 800 efi ho it has about 100hrs. I was riding in welch,wv. And burn't my belt. Took it to the shop and when i got it back it would start [email protected] at full throttle for about 30 min. After that it will run good but at 50 mph it starts missing again. I took it back to the shop they couldn't find the problem,polaris told them to change the belt(no help).i changed the sparkplugs and clean the filter(no help). Has anyone had this problem,please help. Thanks.