I have it - TURNIGY HP50 50cc.
My motor have a broken rotary valve ( crack )/ i break in only 2 hour. [:@] Max RPM - 5800@3W 22x10
see [link]http://www.youtube.com/watch?v=8nwQvrUja70[/link]
Service Hobbycity does not work. I have written already five letters - deaf silence.