If you pull the pipes and look into the exhaust port, should you see piston or valve? Seems to me the valves should be down, since they don't open up 'til higher rpms. But maybe the servomotor closes them once the motor starts. Mine are up and I need to know if I have a problem.
NOT TAKING LIFE FOR GRANTED!! LOOK AT MY AVATAR...THOSE ARE FLAT LINES!</span>
I have a 01 600 and it seems to me that with the motor off the valves are down. You could take the cover off the servo and watch the pulley when you start it to see if it moves but on mine the servo doesn't work untill 7grand or so. I haven't looked in the exhaust ports so I don't know if you can see the valves or not. If nothing else you could support the back end safely and run it up while watching the servo with the cover off and see if it cycles.