Displacement / horse power increase - swappable parts

[Quimrider]

To avoid any confusion with this topic:Convert your GZ250 into a 346cc!!! THERE IS NO BIG BORE KIT FOR THE GZ250. ALSO TO ABOUT 99.999999991% OF THE POPULATION THE COST THAT WOULD BE INVOLVED IN COMING UP WITH YOUR OWN BIG BORE KIT DOES NOT MAKE SENSE. If you would like to discuss the nonexistence of a big bore kit or the fact that modifying the engine is too expensive, please do so in the thread above.

This thread is to discuss which engine parts are/are not interchangeable with the GZ250's engine and various methods one could do to increase displacement and/or horsepower. Additionally I'd like to entertain the topic of potential engine swaps as a means to get more juice out of the GZ250. For example I have read about a Honda Rebel that had a diesel engine shoe horned onto it.

Please minimize speculation/opinion and stick as close as possible to the facts.

One engine of interest is that from the DR350. It is very similar to the GZ250 engine. The DR350 has a 79mm X 71.2mm bore and stroke. The GZ250 engine is 72mm x 61.2mm bore and stroke. Aside from custom exhaust work, the main obstacle from simply swapping the top half of the engines is that the DR350 engine has a 10mm longer stroke. If I ever get my hands on a DR350 cheap enuff I will attempt to put the DR350 engine on the GZ250.