ASP 52 2 Stroke Super Series 3
Since it is crapping out at 3/4 throttle or better, it doesn't seem to have a thing to do with the low end. Again, check for adequate fuel flow, proper clunk function, decent size tubing going to the clunk, etc. You might also check the spraybar. The slit in it should face downward. Are all engine screws tight? Best of luck. It HAS to be fixable.
Ernie