RE: A PUZZLING SITUATION FOR SURE
Hi
I happen to have the exact same problem on a DA50r that used to belong to me now is my Buddies. This motor has been flawless for the past year.
It just dies anytime Power is advanced over 5300 RPM every time.
I personally changed Fuel systems Batteries Clunks and filters. Removed the Carb screen replaced the Spark Plug and still no luck.
DA was called and they said it might have sucked the Gasket between the phenolic Block and the Carb but it was OK.
I have decided it's either the Ignition Module or the Carb has just went bad. The Carb going bad does happen as I have seen this twice in the past.
Best of Luck maybe just send it in.
Ian