Shifting problems

cubedean Posts: 670
edited September 2014 in Workshop
I have converted my bike from 7 speed to 10 speed using downtube friction shifters.

It shifted perfect with the 7 speed cassette, now i've converted to 10 speed it will only shift into the 8th cog up. Do I need to get some more tension on the cable or am i struggling because the deraillure doesn't quite have the range?

Shimano Dura-ace RD7401 which looks like a short cage to me.