My brother replaced his Pure Polaris pipe with a full Yoshi system and he's at least a quadlength slower than he was before. The plugs look good and he's tried different mains and clip postitions with no better results. Is it possible that the Yoshi system is actually making less HP than the White Bros. slip-on?

 

I have heard of this with some other pipes. The Pure Polaris is a great pipe. I traded mine for a HMF, and wow.......I'm glad I did. IMO I think it's better then the Pure polaris....but it is also louder to.