The Finished Chip Beck Spec CB1100-PHOTOS

[ChipBeck_imp]

There is no such thing as good back pressure. That is a never dying fallacy. An engine is an air pump. Anything that makes it less efficient is bad.

The important tuning part is exhaust pulses, and there are many variables to that- pipe diameter, length, transitions, bends, collectors, cats, etc.

Once the cat is removed, you may need to tweak the tune a bit, but the end result would be more power and better gas mileage. Along with a little less weight, a little less heat, a little more sound. Possibly not the sound you want. On cars pulling cats can make it 'raspy' if no resonators are in the system.

Power,

In a 4-stroke engine I agree IF.....as you say, I were to "tweak the tune a bit" to increase fuel to compensate for the increase in air flow to keep the air/fuel ratio near 14.7 to 1. And as I said in my post my bike ran great from idle to red line as it was. Without the cat it would have been a bit lean which would have required a tune adjustment and I don't have the tools or expertise to accomplish that. If I did then my CB11 would have made a bit more power assuming I got it right. Without changing my tune if cat removal improved airflow enough to take my air/fuel ratio from 14.7 to 1 to 16 to 1 then the result would be less power and rougher operation.

So I decided to stay with the cat and my existing tune which my spark plugs indicate is pretty much spot on for my current setup. Cheers.

Chip