Thanks for the input.I'm torn between OEM Yamaha parts and an Eric Gorr top end.I'm tempted to leave the nicer one stock and mod the other bike.I like the idea of being able to drive to Kasson's and pick up a stock Yamaha top end kit.A stock Yamaha cast piston has it's advantages over a Wiseco if replaced often.Years ago I was told that the only replacement for cubic inches is more cubic inches.I assume the same theory applies to cubic centimeters.With that said,I'm torn between stock,134cc's and 144cc's.I have also put some thought into a 153cc kit on one since I plan on replacing the crank anyway...........