The hoses are hard to get on. A little soap or dielectric grease may help to get them to slide on.
+1

...
My bike came with a ratty looking braided main radiator hose.
I took it off, don't remember if that was hard or not. But when I put the new
one on, it went on just so far and that was all she wrote... I wish it had gone
on a little further, and some kind of lube would have allowed for that, but it
has been on for years now with no trouble...
-Mike