....informed responses please. Taken petcock apart twice, replaced rubber gasket in petcock today....COMPLETELY clean, the entire petcock assembly looks perfect, diaphrams, spring, gaskets are all fine/clean, 2 pickup screens; reg. and reserve, are as new, no junk, no dirt ANYWHERE in assembly. Fuel system is fine until switching to reserve, then....no fuel flow at all. bike runs/idles PERFECT...until switching to reserve. I am thinking next thing to do is replace the 3 fuel lines attached to the petcock.....but they look fine, still I will replace them. anybody got facts?? i'm stumped.... vn750 1997, 15,000 miles...almost flawless, superclean, near mint...looks new...impeccable....ok ,there's a little dirt on the tires.