I'm hoping with an 18" rear tire you'll get better tire choices that what you have in the 150/70-17. I guess if it was similar in size to what the KTM 950/990 runs that would work. I believe the 950SE runs an ever narrow rim for even better 18" tire choices, but I'm not sure how skinny you can go on the rear?
BlueLghtning - Follow me on my SPOT Messenger
Mine: 09 DL650, 08 WR250R, 01 FZ1,
Hers: 07 Ninja 650R, 13 CRF250L,
Smugmug Pics - Save $5: Y2l43o9LVBERU