rave valve help

[CLAYL]

My 06 800 won't pull full rpms and it seems to be power valves. Only one is opening and the other opens at full throttle. the one that doesn't open will stay open if I hold it open while revving it up(which seems to get it to rpms).Everything seems to be in working order(hoses,solenoid,and valves). Checkvalve is pretty much new and pointed away from the engine. thanks for any help

 

[CLAYL]

Removed the checkvalve and hooked up direct and both valves opened. Do I need this checkvalve?

 

[blk9038]

did you take sparkplugs out and check for compression with your thumb only (both plugs) you will know right away, also reed valves get old also my 04 the center ones were partly open both cyls, hope this helps.