Why on earth would any body put smaller hoses on any hydraulic system? It is just not done. There are many reasons that it can not be done besides slowing everything down. You could put 2'' hose and not cause any problem, but not smaller. I have always added much more HP and larger pump with larger hoses 1'' or larger. The cylinder does not know the difference except it moves faster. And there is no danger in damaging the system or cylinder because most systems top out at 3,000 psi. There are numerous places to order ready made hoses that are inexpensive. Also do not forget the system needs to be filtered. So if you are upgrading add another filter or get a larger volume one. Thanks