A common point of failure, I believe, and no longer available. I've just managed to get one from a guy in Milwaukee which was NOS.
There's a discussion on making your own
http://www.sohc.co.uk/index.php/topic,3391.msg12852.html#msg12852 If you want to go down that route be aware that the actuator end starts life square and flat. The little dimple your old one is worn by the ball bearing. The end that bears on the clutch is radiused - I can't measure it but the rod diameter for the last 20mm is 7.5mm. I'd guess the radius on the end is 4-> 4.5 mm
The overall length is 255mm with a diameter of 8mm.
I can't imagine why Honda decided to make this a 3/4-piece construction with undercuts (or are then some sort of rolled retaining mechanism?). It looks desperately expensive to me!
Well those are the sizes; some hardening may be necessary depending what you chose to use to make it from.
Anyone got any bright ideas for getting the broken bit out without dismantling the clutch? I've tried a drop of loctite on the other bit . . . .