Bogging and hard on fuel

[Greenman22]

Hey guys I have a 2007 mountain lite .. I have a bog at about 6500-8000rpm under load almost feels like it would stall if I held it there .. but as soon as I crack it it’s all there .. what could cause this.. also I feel like it’s very hard on fuel

 

[2stroken]

Is it more throttle position related?

 

[Greenman22]

I have jacked up track and it doesn’t do it .. it’s when it’s under load , example. Going up hill or pulling kids.. it seems like clutching to me , I just don’t know much about it

 

[maim]

throw a new primary spring into it as if it has never been replaced, it can cause weird issues. they get weak over time/milage. had it happen to me on a nos sled i bought while it was under warenty. this site pointed me the right way to fix it.