I live in the UK and own a sabre 1742HS,same problem, used the following to help replace the DRIVE belt.The 1846hv setup exactly matched mine,good luck
go to :-
http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePageServlet_Alt
in Model Search enter 1846hv
click find
click Catalog Search Results 2713-SABRE 1846HV....
click pictorial index
click 1-SABRE 1846hv.....
scroll to 50-1-C18 BELT DRIVES AND IDLERS
ted, June 2008