Loss of topend RPM

[DusterB]

So all of a sudden my M7 won't reach top RPM. (usually 8020) at 9000ft Ran great all last week and then on the trail ride home it just had no power. The bottom still felt good and hooked up well but right about 6200-6400 she didn't want to go anymore. Very sluggish to hit 7000 rpm. SO
Checked the clutching and no broken springs and belt looks ok.
Checked the power valves and they are clean.
Pulled the plugs and they look ok.
No oil leaking nor anything obvious unhooked or broken.

Some threads on this suggest a servo motor issue because it seems like the power valves are not opening. I checked the cables into the servo and everything seems ok.

She is very low on gas but I've ran it that low before with no issues. (about inch left)

Any Ideas?
:beer;:beer;

 

[bigcat_ak]

Power valves not opening.

 

[Killerk]

Did you check the spring, weights, and rollers in the primary?
Doubt it would happen on the trail on the way back, but if you have a bad roller and a weight hanging up it will not hold its R's.

 

[Vern]

maybe its sucking in water from somewhere, had this happen when tinkering with airbox ideas and it runs just like if the powervalves dont open.