errm what grage of wire ?

[Scotty]

what sort of wire do i need to connect the starter motor to that other bit of electrical gubbins ?

all i know is it s a blody thick one ?

manual says starter motor is 0.7 kW
so 700/12 =60 ish i want a 60 amp cable do i ?

[slob]

I'd say more like 90A. 60A would be required, 150% would be over-engineering for safety. What's wrong with the original? Wouldn't a stock replacement be cheap/easy enough to get hold of?

[PaulS]

As Slob says I would go significantly thicker than 60A, not just for safety, but also to keep the resistance down. It seems (particularly in the USA - 6awg (http://www.powerletproducts.com/products/ducati_starter_rewire.php) ) quite common to fit thicker cables than standard on both sides of the starter solenoid and the battery earth to help with starting. I get the impression that you find the battery's ability to start the S4 a bit marginal (as I have also) so using thin cables won't help too much.