29mm - only because Buzz told me so. Again, his words were - "every track comparison we've done and seen those 29's came out on top". To see these 29's next to the stock 28's it's like drinking through a big-mouth jug and a straw - they are 29mm al of the way through whereas the only the lip is close to 28mm on the stockers. I personally don't think I'm using all of the carburetion available on the 29's.
I've got 836, big cam, Kerker, and a ported head and I have to ease into the throttle with these 29's. The bike will bog/stumble if opened abruptly anywhere less that 5,000 rpm. My seat dyno says they are only "slightly" better than stock and only at the 9,000 up range. I say this based on the stock 28's (now with Seaweb/Derek) the front would start lifting the front on accel at 8,000 in 2nd and hold it there until about 9,500 rpm. With the CR29's - the lift is still in the 8,000 area, but doesn't set down until it's in the 10,200 range.
The off-idle and mid-range was better with the stockers. It started better, drove better period. I hope Derek found the same - those were jetted and set-up nice. The CR's big venturis are over-sized and don't mix as well in my opinion until the rpms get in the 5 digit range. That's my butt dyno again.
Gordon