I rode another 100 miles or so with my wife 2-up today. It's like a whole new bike. With the increase in torque and hp, there is practically no difference solo and riding 2-up. I'd always had thoughts about possibly going back to the 17T sprocket, but no more! Although the gears are taller, the bike accelerates and pulls through the gears like never before. In every gear there is more power and usable range. I still haven't been able to really go for it as I'm trying to take it easy the first 500 miles, but it's like I own a sport bike now. I can't express how much difference the BB did. All I can say is I could give a crap about a larger twin cruiser right now. I've always loved the handling and look of my bike, now there's this huge difference in power.
If there had been a $1000. or $1500. option for more power and torque when I bought the bike, I probably would have paid it. The difference is worth way more than that. I wish I'd done it sooner.
