[Trey54]

Hope this helps somebody trying to speed up their Super X3:

for US ordering

QTC410 - Component Data Base

search for part no. QPMHTD5S15040F08

you will have to bore out the diameter to 14mm and key to fit the machine.
this means buying a broach and press to key pulley. Also you will probably want to tap a set screw into into it.

Belt is also req'd:
QB-HTD5-0450-15

[Thorn3]

I realize this thread is years old, but a company called 'Misumi' is available online, where you can order pulleys that fit your needs. No more need to order a pulley in a stock configuration, then have to machine it. Just order it the way you want it. Total cost is far less and its at your door in about a week. I used them to create two new pulleys for me, for my SX3. They also have a belt calculator, so ordering the right belt is a breeze.