I believe stock is 40 or 42" I put a 42" braided stainless line on with my risers. What I would do if I were you is bolt up your bars, but leave your old bars attached to the controls (it helps if you have a buddy as you are gonna need 4 hands) and then lay a towel over your triple trees and tank and compare your old grip position to the new one. The difference in height is gonna be the difference in length you are gonna need. Another trick is to take a piece of vacuum tubing or something similar and mock up your brake line with the new bars, as if you buy a line that is too long, it will be, well, too long. I could have got away with a line that is a little shorter, but it is ok.
When it comes to putting on the new line, here is a tip,
DO NOT remove the master cylinder cover before you disconnect the old brake line. Disconnect the top banjo bolt (on the master cylinder) first and have your new line ready to go in your other hand, remove the old one and replace the new one as fast as you can, you won't lose hardly any brake fluid, then disconnect the caliper. After you reconnect the caliper,
THEN remove the master cylinder cover and let gravity push the fluid through the line, and put a piece of hose on the bleeder into a small bottle of brake fluid. I have done a few of these and it is much, much easier to do it this way, just make sure that the master cylinder doesn't go dry as it is a royal pain to get the air out of it.
One more thing on this job: Be very very very careful about the brake light switch as they break very easily. The first thing I do when I am touching anything on the right side controls is remove the brake lever and it is the last part I replace. I have broken two of these now and almost broke the one on my bike. They are $25 from Hundred Dollar, for a $2 switch.
Let me know how the job goes, and if you have any questions, I'll do my best to help out.
Someday I want to open my own bike/speed/chrome shop so I can put this knowledge to good use......
THE:rider
ENNSYLVANIA