Powervalve issue?

[SpeedyManiac]

FYI guys. As mentioned before, we were having troubles with a poorly running 2011 EC250. By poorly running, it was weak off the bottom then hit really hard in the midrange and pulled hard right up to wide open throttle. Jetting helped but regardless of the jetting, the underlying problem remained. With Glenn's advice, I started looking into the powervalve and sure enough, it was not staying seated closed, even at idle, and would open as soon as I blipped the throttle.

I ended up putting a 1.5mm washer as a shim under the spring in the governor under the right side engine cover. You don't need to pull the clutch over or waterpump cover but you do need to drain the coolant. It was pretty easy to do and now the bike performs as it should. It makes great bottom end and lugs down better than any other two-stroke on the market, yet will rev up and run with any 450 in the open stuff.

When I get time, I may try going to an even thicker shim just to see the difference. If you're looking for a shim, a washer the same size as the one that goes between the clutch basket and inner hub works perfectly.

Oh yeah, for jetting we're using a 172 main, 38 pilot, N8RH needle (KTM) in the 4th clip and air screw is 1.5-2 turns out depending on the temperature. Elevation is 2000-4000 feet. Once it warms up more I may drop the needle and switch to a 35 pilot jet.