your single-rotored bike has great stopping power as it is. it's actually one of the best-stopping bikes on the road from 60-0.
so why bother with a dual disk upgrade? there are two major reasons that i can think of...
1 - brake fade. your bike stops VERY well with one disk if not forced to do so repeatedly in a short time frame. for example, if you're dicing up some twisty backroads. accellerate, brake for corner, repeat. as your single-disk gets hot hot hot, your braking performance will fade.
2 - even workload. having a 2nd disk will distribute the load of braking force evenly across the wheel and forks.
as for what you need, martin's right that you'll need a rotor, new lines, and a caliper/pads. you'll also probably need a new master cylinder since the unit on single-disked bikes displaces less actual fluid with each lever pull. with that smaller master cylinder, you'll pull the lever right to the bar and not have sufficient stopping power. here's a great excuse to get a radial master cylinder (woo hoo!). the stock "goldline" unit off any "S" model monster or the s4 will do nicely though.
You don't have to replace the wheel but it will still be plenty expensive.
I have a 2000 M750 with single rotor, and I actually think it would be better to move up to a 2001 with duel disks and a tach.
And go up to 900 while I'm at it! 8)
Like others have said already, you'll need rotor, caliper, new master cylinder with remote reservoir, new brake lines, pads and mounting bolts.
I was thinking about it as well, but after addidng up all the hardware costs I figured it was not worth it to me.
I wanted it for looks, plus I liked the remote reservoir idea so I could put CycleCat clipons. I don't track the bike, so single rotor has enough stopping power for me and I'm yet to experience brake fade
I purchased (2) gold line calipers w/pads lines and full lever (still all assembled) which was all taken from a 996, off of Ebay for $215 w/shipping... buy two new rotors from Motowheels and you have a new front brake setup for less than $500... Its totally worth it!! ;D
i was under the impression the m/c that came with the single-disker's has a smaller bore than those supplied with dual's. since it's gotta displace fluid for two calipers, i think you might be pushing it. i wonder if there was a variation of m/c's ducati provided for single-disker's over the years?
anywho, if you're upgrading to a 2nd disk, may as well consider upgrading the m/c for better leverage and feel anyways.
as for new parts, yep... shouldn't be TOO pricey as you point out, but the '00 m750 uses the 65mm mount as opposed to 40mm for the caliper. and as for the rotor itself, i'd definately recommend going NEW with that. how much would it suck to buy a used rotor, get it mounted up, and find it to be marginally warped. no warranty there...
yup, 2000 m750 uses 65mm mount. Also, you'd want same design rotors on both sides, right? Then you'd need new lines, bolts, little metal/rubber thingie holding and directing second line at the fork... these will all add up.
Unless you get lucky with ebay, it will run well over $500. And you will need a new master, otherwise your lever will travel all the way to the grip, and levers on 750 are not adjustable
brembo coffin master cylinder has a reservoir with less capacity than the two calipers it feeds. thus, if you put in new brake pads and fill up the reservoir and then use up the pads without adding more fluid, it will get air into the system. then when you go to put in new pads, you have to remove fluid from the reservoir.
if you buy new rotors, buy the great stuff... www.braketech.com (pic of stainless version on my old 916) the ductile iron rotors are sawed off from a continuous bar. they hold up, not like the cast ones found elsewhere on the market (which allegedly will crack ???) anyhow, i've used stainless, brembo cast iron, and the braketech ductile iron and the BT brakes are head and shoulders above the rest.
i suspect you could buy a single BT ductile iron rotor FIRST and probably be happy with that. in fact, i'm contemplating doing a dual to single rotor conversion to my m900... see, my aprilia rs250 race bike uses two stainless rotors, but for my aftermarket wheel, i put on a single BT ductil iron rotor and it stops better than the dual stainless rotors. 8)