Who has info to what initiates the exhaust valve solenoid to open and close? I thought it was possibly rpm related to throttle position. Problem is with two of them (rmk 600 ho) sitting side by side at idle one is open and the other is closed. Also can it be eliminated what is its real function?

I eliminated mine on a 2001 prox 440 motor. I went to the dealer and bought xc500 ev springs (blue/white if I remember right) installed and just capped the nipple out of the ev.

Your CDI sends the info to the solenoids at a programmed rpm to open/close.

I played with all kinds of things on mine and this worked the best.

should be closed at idle I believe

You should be able to eliminate it by just connecting the line coming out of one of the valves to the other valve, (or just plug the nipples on the valves). Thats what my friend is doing on all of the 440-600 conversions he has done. Perhaps you need to change the springs after this treatment, I´m not sure...

If i´m not misstaken the purpose of the solenoid is to keep the valves from opening, so with solenoid removed the valves should open earlier.

Both valves should be closed at rest or idling. Sounds like they need cleaning. No need to remove the solenoid.

Just fyi, I suggest routing a hose from the solenoid vent through a self made hole in the shock tower area to eliminate the oily mess in the engine bay. My 07 had a hose install but it was routed out next to the front cooler and was pinched in that area, a potential cause of non functioning valves and high RPM power loss.