While I've posted to this thread a couple of times already, I thought I'd add another couple of cents worth.

As I've already mentioned in my previous posts, we've switched from the FMF Fatty to the Toomey B1. Our motor has been extensively modified for TT/Flattrack racing, with top-end style port work. With the B1 pipe, we have more power at all rpm ranges, not just the top-end. It produces a broader power band, as well as more peak power, than does the FMF Fatty.

Even if all we did was trail ride, I'd still prefer the Toomey B1 pipe over the FMF Fatty.

If you can compare the two pipes side by side, you'll note some differences in the builds of the pipes. The Toomey has a longer head pipe coming out of the cylinder, which will promote better torque in the lower rpm ranges. It also has a larger expansion chamber which gives it larger volume, thus producing more peak horsepower.

Regards,

Rog