Originally Posted by makoman1860

Hey Dave,
I myself have re-timed the ports on one of my engines, along with a new intake manifold, walbro "pumper" carb , changed ignition timing and tuned pipe/silencer setup. The end result?-The power of a 1970's vintage 50cc dirtbike engine, with the lifespan of a yugo. In all seriousness the crankshaft is the weak link in the engine for power development, with the driveline short behind. The crankpin to crank-web fit isnt the greatest, and the materials very 1940's vintage (cheap 1940's). Also the piston being a long trunk design is too heavy for high RPM use. After that ordeal I stuck to just making them decently reliable with good runability, and have been having a ball with that!