Factory b pipe - limited chamber. The pipe comes with two diff length chambers. Mod pipe is short, limited pipe is long. Limited pipe moves the power band down a few hundred rpms. Noticeable difference between the two should be close to 0 though.
Uh,they are made for a Yamaha like I previously stated and the manifold will not mount on a Kawi. B is just designation for the Yami head pipe. If you get a Coffmans and have any ?'s you can call Gary Coffman and he is very helpfulwhat do you mean "really hard to make work" on a kawi ???
http://www.pwctoday.com/showthread.php?t=401894ya im looking at a factory pipe. that they are calling a fatcory b pipe . it looks like the middle pic. with a spout out the bottom for the pipe to run back to the water box side