Hi!
I have a Tempo Sachs Transporter 125/175cc and I'm having trouble with the third gear. When I shift from second to third gear or from fourth to third, this happens: the gear pops out and goes into neutral, causing the engine to rev freely. When I'm riding, it keeps jumping out of third gear. I've tried replacing all the gears and bearings with new parts. The gear selector seems to be in order. I've consulted several mechanics who are familiar with these types of engines. They have opened the gearbox and confirmed that everything is correctly assembled and looks normal. We're stuck and struggling to figure out the problem. Has anyone experienced similar issues or have any suggestions on what it might be?