Hello Pros.
I #ve bought an older YS-53 second hand these days and try to run it smoothly. I've made some basic successes and some flights allready but I've had some bad inflight motorstops also.
I read a lot and fix some basic issues.

1. I'm using Rapicon Heli 20 (the best i could get in Germany)
2. 11/6 Prop
3. Fuelsystem is leakless and pressurizes fine. An oneway valve is installed.
4. Valves are set to 0.04-0.06 mm. the Cover is tight.
5. Regulator is flush

The Motor runs fine, but after a while at full throttle I can hear detonations and suddenly the Prop is off...
setting the carb rich, the engine has no power and looses speed till it dies.

Setting the air bleed screw for idle mix, I've noticed that it looks very different to the YS-63S I own also. the blueprints I've found online are different to (same as YS 63).
Is my YS-53 an really early version with a different layout? Do you have any sources for early YS? Can, and should I upgrade? Does the low end effect the full throttle?

Thanks for any help and please apologize my english!