I think one of my clutch springs may be weak but would like to know what opinions those more knowledgeable than I may have.Yesterday I was on an old logging road running along at about 70-75mph for about 1.5-2 miles and everything seemed to be working fine until I tried to feed more throttle in and all the engine would do is bog.The tach was reading about 7000 and would'nt go any higher.At low speeds it seems to be fine,the clutches are shifting right,the revs are there when I open the throttle(83-8400) but it just seems to be acting strange on top end.The primary is set up with HC's(red spring) and a green yamaha in the secondary.This is a new problem to me and unfortunatly I have'nt had a chance to investigate anything today yet as far as bushing wear etc.Anybody have any thoughts?Thanks. 
Sounds like a backshift problem. On warm days when the belt gets hot with aggressive clutching the sled won,t backshift in the midrange. Let off the throttle , get your speed down & pin it again.
backshift problems
Thanks for the reply Turk.The setup I'm using is one you recomended for that sled with HC's,green spring w/50-38 helix(Dalton) and has worked fine until the other day,that's the first glitch I've ever had.
Thanks for the reply Turk.The setup I'm using is one you recomended for that sled with HC's,green spring w/50-38 helix(Dalton) and has worked fine until the other day,that's the first glitch I've ever had.