Been looking into the Yost Power tube CV-40 master kit for the 1200. I know it's a little pricey at $95 but it seems to take the overall guesswork outta performance rejetting. Plus the tech support (according to many people's personal reviews) is second to none. http://www.americanthunderbike.org/p...views/yost.php
Anybody here have any experience using the Yost power tube kits?

 

I put one in an S&S G carb and you could really notice it run better, a lot smoother.

 

Put one in my CV40, took it back out. Too rich. Gas mileage sucked. For best results using a CV40 carb, do NOT drill the slide or change out the spring. Especially on a heavy bike, you kill the low end torque. Jet it properly, and use a 1989 Sporty needle. Put it on the dyno and use the sniffer to set your A/F ratio. Ride, enjoy, repeat!