Here is my before and after with the stock 2005 carb jetted right compared to a YFZ FCR straight bored to a 44.
I picked up 2 HP across the board as you can see which actually seems low. I also ran a max speed test up Olds to compare the 2 carbs in the same weekend. Max speed with the stock carb was 49mph and max speed with the 44 FCR was 52 mph!!! I thought that shows how big of a difference the carb can make.
My 2 dyno runs were not done back to back. The fcr was put on a couple of months later when the motor had more time on it so that could be why the difference isn't greater.
Motor: +3 hot rods crank unbalanced, CW BB kit, early hrc cam, venom porting, stock size valves in head, Rossier pipe, dyna box, Dasa intake + filter with stock snorkel and air box, 13:1 CP piston, pump gas, tps hooked up, etc.
The carb gives the bike better throttle response in the dunes. When racing the hill, the bike pulls much harder throughout the rpm range.
This stubborn s.o.b. finally hit 60HP with a very broad curve. I am lovin' this bike now.