hi guys

I just had a miserable time at the last race meet on my mc21

hard starting, no power, traced to a range of faults including a stuck ring and and dead battery

once these were sorted it appears the valves are still playing up and to be different they open but dont close

My normal means of setting is to unplug the tps, yurn it on and the valves cycle to open

This only happens now with the motor started and when moved to open they stay there regardless of revs etc

we have checked the tps which appears to be working and swaped the servo motor out with one from my 28 (so know to be good) but no change

does anyone have any ideas? I'm getting desperate as the last round of our race series is comming up and the a four strokes to rubbish

Paul