Hey Apex!
I did get your PM, was checking on the drivers for you.
After major hunting, came up with nothing.
4strokelover is correct, for some reason doo doesn't offer the drivers separate anymore.
I would bet they have a production shortage on them and only provide them on the shaft to keep the Doo guys going first.
(As opposed to us! lol)
I do have one set brand new on the shaft that I can sell for $160 shipped.
A bunch of Doo guys want them for the same reason, they can't get them either!
The cost would be the same on, or off the shaft.
The Doos are the toughest from what I have heard.
You will have to shim them for the Yamaha shaft.
Showed how to shim them here.
http://www.ty4stroke.com/viewtopic.php? ... c&start=15
Hope this helps!
Will keep trying to find a valid Doo number for just the drivers.