Hey BobCat, is your Sabre fuel injected? If so I believe it would be single fire, otherwise if you have carburetors, dual.
Here is an excellent install guide here:
http://www.eurekaboy.com/shadow/tach.htm and here:
http://www.750ace.com/forum/viewtopi...4f46e40a7b10af. Read through them thoroughly.
Here is when I put one on my Spirit:
http://www.750ace.com/forum/viewtopi...4f46e40a7b10af.