748E uses a different yoke/stem due to the fact that it doesn't have adjustable headstock. The stem looks like an old school SS/Monster type, rather than the sleeker looking 916 version. Edited to ad, like this; http://www.ebay.co.uk/itm/DUCATI-74...pt=UK_Motorcycle_Parts_13&hash=item1e7e5d15b8
As Dukedesmo says you need the 748E bottom yoke and stem (I did have one but I'm pretty sure I've thrown it out). The top clamp is the same though so you only need the bottom and stem. Example Edit: damn duke you beat me with an example!
You know the S4R yoke looks very similar, considering the shortage of cheap 748E yokes, is it worth measuring S4R part??